Gas overcurrent detection method and diaphragm gas meter

Abstract

The present invention discloses a gas overflow detection method and a diaphragm gas meter, belonging to the technical field of gas meters. The method comprises: using a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter; when the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first counting threshold, using a second timer with a second timing step to measure the subsequent pulse time interval of the diaphragm gas meter; the second timing step is less than the first timing step; when the count values ​​of the second timer in the pulse time intervals of a preset number of consecutive times are all less than or equal to the second counting threshold, confirming that an overflow anomaly occurs; the first or second counting threshold is the count value corresponding to the pulse time interval corresponding to the overflow threshold when the first or second timing step is used for measurement; the preset number is less than the number of complete pulse time intervals that pass within the detection time limit when gas is leaking at the overflow threshold. The present invention can timely and accurately detect gas overflow anomalies.

Description

Technical Field

[0001] The invention relates to the technical field of gas meters, and in particular to a gas overflow detection method and a diaphragm gas meter. Background Art

[0002] During the use of diaphragm gas meters, such as electronic intelligent diaphragm gas meters, the gas flow rate through the gas meter may be greater than the maximum flow rate for normal operation of the gas meter due to the mismatch between the meter specifications and the actual gas usage scenario, or abnormalities in the gas-using equipment. When the actual flow rate continues to be greater than the maximum flow rate for normal operation of the gas meter, it will cause damage to the diaphragm gas meter itself and affect the metering accuracy of the meter. Therefore, it is necessary to monitor the overflow of gas so that the valve can be actuated in time to cut off abnormal gas use.

[0003] However, currently, the overcurrent detection scheme of the membrane gas meter in the related technology has poor accuracy, and it is difficult to complete the gas overcurrent detection in a timely and accurate manner within the time limit requirement of the overcurrent abnormality detection. Summary of the invention

[0004] The present invention provides a gas overflow detection method and a diaphragm gas meter to realize timely and accurate gas overflow detection.

[0005] In a first aspect, an embodiment of the present invention provides a method for detecting gas overflow, comprising:

[0006] Measuring the pulse time interval of the diaphragm gas meter using a first timer having a first timing step length;

[0007] When the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first count threshold, a second timer with a second timing step is used to measure the subsequent pulse time interval of the diaphragm gas meter; wherein the first counting threshold is the count value corresponding to the pulse time interval corresponding to the overcurrent threshold when the first timing step is used for measurement; the second timing step is less than the first timing step;

[0008] When the count values ​​of the second timer in a consecutive preset number of pulse time intervals are all less than or equal to the second count threshold, an overcurrent abnormality is confirmed; wherein, the second count threshold is the count value corresponding to the pulse time interval corresponding to the overcurrent threshold when the second timing step is used for measurement; the preset number is less than the number of complete pulse time intervals that pass within the detection time limit when the gas is leaking at the overcurrent threshold.

[0009] Optionally, the first counting threshold is a result obtained by dividing the pulse time interval corresponding to the overcurrent threshold by the first timing step and rounding up;

[0010] And / or, the second counting threshold is a result obtained by dividing the pulse time interval corresponding to the overcurrent threshold by the second timing step and rounding down.

[0011] Optionally, the second timing step is 0.5%-5% of the first timing step.

[0012] Optionally, the first timing step is 1 second, and the second timing step is 10 milliseconds.

[0013] Optionally, the gas overcurrent detection method further includes: when the count value of the first timer corresponding to the current pulse time interval is greater than the first count threshold, continuing to use the first timer to measure the pulse time interval of the diaphragm gas meter.

[0014] Optionally, before using a second timer with a second timing step to measure subsequent pulse time intervals of the diaphragm gas meter, the method further includes:

[0015] The number of continuous overcurrent pulses is recorded as 1;

[0016] When the second timer is used to measure each of the subsequent pulse time intervals of the diaphragm gas meter, the method further includes:

[0017] When the count value of the second timer corresponding to the pulse time interval is less than or equal to the second count threshold, the number of continuous overcurrent pulses is increased by 1;

[0018] When the count value of the second timer corresponding to the pulse time interval is greater than the second count threshold, the number of continuous overcurrent pulses is reset to zero, and the process returns to the step of using the first timer with the first timing step to measure the pulse time interval of the diaphragm gas meter;

[0019] Wherein, when the number of continuous overcurrent pulses reaches the continuous overcurrent pulse number threshold, it is confirmed that an overcurrent abnormality occurs; after confirming that an overcurrent abnormality occurs, it also includes:

[0020] The number of the continuous overcurrent pulses is cleared, and the process returns to the step of using a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter.

[0021] Optionally, the threshold value for the number of continuous overcurrent pulses is less than or equal to a result obtained by rounding down the detection time limit divided by the pulse time interval corresponding to the overcurrent threshold.

[0022] Optionally, when the first timer is used to measure the pulse time interval of the diaphragm gas meter, the second timer is turned off.

[0023] Optionally, while confirming that an overcurrent abnormality occurs, the method also includes:

[0024] Generate an over-current alarm signal and control the valve to close.

[0025] In a second aspect, an embodiment of the present invention further provides a diaphragm gas meter, comprising: a controller, wherein a first timer and a second timer are provided in the controller; the controller is used to execute the gas overcurrent detection method provided by any embodiment of the present invention.

[0026] In the gas overflow detection method provided by the embodiment of the present invention, during the gas meter leakage process, the pulse time interval between each two adjacent pulses is first measured based on the first timer with lower timing accuracy to roughly determine whether overflow currently occurs. If so, the second timer with higher accuracy is then enabled to accurately measure the subsequent pulse time intervals, so as to accurately determine whether overflow actually occurs in each subsequent pulse time interval. When overflow occurs in a preset number of pulse time intervals in a row during the measurement process of the second timer, it can be accurately determined that overflow actually occurs. And by setting the preset number to be less than the number of complete pulse time intervals that pass within the detection time limit when the gas meter leaks at the overflow threshold, it can be ensured that overflow detection is completed within the specified detection time limit. Therefore, the embodiment of the present invention can timely and accurately realize gas overflow detection, which is conducive to timely abnormal control.

[0027] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a flow chart of a gas over-flow detection method provided by an embodiment of the present invention;

[0030] Figure 2 It is a flow chart of another gas overflow detection method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0033] As mentioned in the background technology, the overcurrent detection scheme of the diaphragm gas meter in the related technology has poor accuracy. The following is a brief explanation of the reasons for this problem: For the overcurrent detection of the diaphragm gas meter, the more common technical requirements of the gas companies in the industry are to complete the overcurrent detection within a certain detection time limit and execute the corresponding treatment measures. The following is an example of a detection time limit of 2 minutes. At present, the conventional detection method is to calculate the gas volume passing through the gas meter every 2 minutes, and convert it into an hourly flow rate to determine whether the hourly flow rate is greater than the overcurrent threshold of the gas meter. If the hourly flow rate is greater than the overcurrent threshold, it is determined that overcurrent occurs. However, due to the pulse detection characteristics of the diaphragm gas meter, the related technology usually confirms whether overcurrent occurs within 2 minutes by counting the number of pulses within 2 minutes. However, if there is no overcurrent in the first part of the current 2 minutes, and overcurrent occurs in the remaining time, it may be that the number of pulses in these 2 minutes will not exceed the pulse number threshold corresponding to the overcurrent threshold, so that there will be no overcurrent prompt within the current 2 minutes, and overcurrent can only be detected within the next 2 minutes. Therefore, the time for detecting overflow in the related art is actually generally greater than 2 minutes, and the time from the beginning of overflow to detection is usually in the range of 2 minutes to 4 minutes, which cannot accurately and timely realize gas overflow detection as required.

[0034] The embodiment of the present invention provides a gas overflow detection method, which can be applied to a diaphragm gas meter, such as an electronic intelligent diaphragm gas meter, and can complete the gas overflow detection timely and accurately within a specified detection time limit. Figure 1 FIG. 1 is a flow chart of a gas over-current detection method provided by an embodiment of the present invention. Figure 1 The gas over-current detection method comprises the following steps:

[0035] S110, using a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter.

[0036] For ease of explanation, the following is a brief description of the gas flow rate monitoring method of the diaphragm gas meter. In the diaphragm gas meter, the detection diaphragm reciprocates during the gas flow process. When the gas volume passing through the diaphragm gas meter reaches the pulse volume equivalent, the diaphragm completes a cycle of movement. Each time the diaphragm completes a cycle of movement, a pulse can be provided by a conversion component (for example, including a Hall element). The pulse time interval can be understood as the time interval between two adjacent pulses provided by the conversion component, which can actually represent the time elapsed when the gas flow through the diaphragm gas meter reaches the pulse volume equivalent; the ratio of the pulse volume equivalent to the pulse time interval can represent the gas flow rate. The diaphragm gas meter can realize real-time monitoring of the gas flow rate by continuously measuring the pulse time intervals corresponding to each pulse volume equivalent when circulating.

[0037] It is understandable that the first timer can continuously measure the pulse time intervals that the diaphragm gas meter passes when each pulse volume equivalent is passed. The count value of the first timer when measuring any pulse time interval is equal to the result of dividing the pulse time interval by the first timing step and rounding, for example, rounding up / down.

[0038] S120: When the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first count threshold, a second timer with a second timing step is used to measure subsequent pulse time intervals of the diaphragm gas meter.

[0039] Among them, the first counting threshold is the count value corresponding to the pulse time interval corresponding to the overcurrent threshold when the first timing step is used for measurement. Exemplarily, the overcurrent threshold can be greater than or equal to the maximum flow rate (denoted as Qmax) for normal operation of the gas meter, for example, slightly greater than Qmax, to provide a certain detection margin to avoid false alarms due to accidental factors. The overcurrent threshold can specifically be 1.2Qmax. The pulse time interval corresponding to the overcurrent threshold can be calculated based on the overcurrent threshold and the pulse volume equivalent. For the sake of convenience of explanation below, the pulse time interval corresponding to the overcurrent threshold is referred to as the pulse time interval threshold.

[0040] When the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first count threshold, it indicates that the gas flow through the diaphragm gas meter has reached the pulse volume equivalent in a time shorter than the pulse time interval threshold, and it can be preliminarily determined that overcurrent has begun to occur. It can be understood that the current pulse time interval is the time interval between the occurrence time of the current pulse and the occurrence time of the previous pulse. When the current pulse time interval is less than or equal to the pulse time interval threshold, the current pulse can be recorded as an overcurrent pulse.

[0041] The second timing step is smaller than the first timing step, that is, the second timer has a higher precision than the first timer, and can achieve more accurate timing. Then, when it is preliminarily determined that overcurrent has begun to occur based on the count value of the first timer, the second timer with higher precision is enabled to more accurately calculate the next pulse time interval to accurately determine whether overcurrent has indeed occurred.

[0042] S130: When the count values ​​of the second timer in a preset number of consecutive pulse time intervals are all less than or equal to the second count threshold, it is confirmed that an overcurrent abnormality occurs.

[0043] The second counting threshold is the count value corresponding to the pulse time interval corresponding to the overcurrent threshold when the second timing step is used for measurement. The count value when the second timer measures any pulse time interval is equal to the result of dividing the pulse time interval by the second timing step and rounding, for example, rounding up / down.

[0044] The preset number is less than the number of complete pulse time intervals that pass within the detection time limit when gas is leaking at the overcurrent threshold. Exemplarily, an upper limit value m of the number of detection times can be determined by rounding down the ratio of the detection time limit and the pulse time interval threshold. The upper limit value m of the number of detection times is the number of complete pulse time intervals that can pass within the detection time limit when gas is leaking at the overcurrent threshold, or the maximum number of pulse volume equivalents that can flow through. The pulse time interval when the count value of the first timer is less than or equal to the first count threshold is used as the first pulse time interval for determining the start of overcurrent. The number of continuous overcurrent detections using the second timer is less than m, and the maximum is m-1, to ensure that the first timer is used in conjunction with the second timer to complete the overcurrent detection within the detection time limit, avoid the overcurrent time being too long and affect the metering accuracy of the meter, and reduce safety hazards. In other words, the preset number can be any positive integer between 1 and m-1. It is understandable that when overcurrent occurs, the gas flow rate flowing through the membrane gas meter is greater than the overcurrent threshold, so the single pulse time interval is less than the pulse time interval threshold. On this basis, measuring m pulse time intervals for overcurrent detection can fully ensure that the overcurrent judgment is completed within the detection time limit. Exemplarily, the selection range of the preset number can also be set to have a certain lower limit value, such as greater than or equal to 5, to avoid false alarms caused by too few pulse time intervals detected, and further ensure the accuracy of the detection results.

[0045] In the gas overflow detection method provided by the embodiment of the present invention, during the gas meter leakage process, the pulse time interval between each two adjacent pulses is first measured based on the first timer with lower timing accuracy to roughly determine whether overflow currently occurs. If so, the second timer with higher accuracy is then enabled to accurately measure the subsequent pulse time intervals, so as to accurately determine whether overflow actually occurs in each subsequent pulse time interval. When overflow occurs in a preset number of pulse time intervals in a row during the measurement process of the second timer, it can be accurately determined that overflow actually occurs. And by setting the preset number to be less than the number of complete pulse time intervals that pass within the detection time limit when the gas meter leaks at the overflow threshold, it can be ensured that overflow detection is completed within the specified detection time limit. Therefore, the embodiment of the present invention can timely and accurately realize gas overflow detection, which is conducive to timely abnormal control.

[0046] Based on the above implementations, optionally, while confirming that an overcurrent abnormality occurs, it also includes: generating an overcurrent alarm signal and controlling the valve to close.

[0047] Among them, the alarm signal can be transmitted to the alarm module in the diaphragm gas meter, and the alarm module is controlled to issue an overcurrent alarm. The alarm module issues an alarm by, for example, at least one of sound, light, and vibration. Controlling the valve to close is equivalent to performing an active valve closing action, which can cut off abnormal gas use in time to prevent the overcurrent from continuing to occur, thereby achieving active safety gas protection.

[0048] On the basis of the above-mentioned embodiments, optionally, when the first timer is used to measure the pulse time interval of the diaphragm gas meter, the second timer is turned off. In this way, it is equivalent to turning on the second timer only when an overcurrent is preliminarily determined based on the measurement result of the first timer, and then precise measurement is required. In the normal gas leakage detection process, the second timer is not working, which can reduce the power consumption of the second timer, thereby ensuring that the power consumption of the diaphragm gas meter is low, and then ensuring the endurance of the diaphragm gas meter.

[0049] Exemplarily, when the second timer is used for metering, the first timer can continue to work, and at this time, only the count value of the second timer can be obtained without obtaining the count value of the first timer. It can be understood that the diaphragm gas meter in the related art is usually equipped with a first timer, and the first timer itself will continue to work during the operation of the diaphragm gas meter. This embodiment is equivalent to adding a second timer on the basis of the diaphragm gas meter in the related art, and the second timer is only turned on when it is preliminarily determined that an overcurrent occurs, and the overcurrent situation itself does not often occur. Therefore, the power consumption increased by adding the second timer is very limited and basically does not affect the endurance of the diaphragm gas meter. Alternatively, when the second timer is used for metering, the first timer can be turned off to further reduce power consumption.

[0050] On the basis of the above embodiments, optionally, the second timing step is 0.5%-5% of the first timing step, which can effectively ensure the measurement accuracy of the second timer. Exemplarily, the second timing step can be selected as 0.5%, 0.8%, 1%, 2%, 3%, 4% or 5% of the first timing step. For example, the first timing step can be 1 second, that is, the first timer can be woken up by a second interrupt; the second timing step can be 10 milliseconds, that is, the second timer can be woken up by a 10 millisecond interrupt. Among them, the first timer can be an RTC (Real-Time Clock) timer, and the second timer can be an ordinary timer, and the two can be integrated into the same controller, such as a single-chip microcomputer.

[0051] Figure 2 FIG. 1 is a flow chart of another gas overflow detection method provided by an embodiment of the present invention. Figure 2 The gas over-current detection method comprises the following steps:

[0052] S201, calculating the pulse time interval threshold T1, the first counting threshold CN1, the second counting threshold CN2 and the continuous overcurrent pulse number threshold N1.

[0053] Among them, the pulse time interval threshold T1 is the pulse time interval corresponding to the overcurrent threshold. This step is equivalent to the preparation work before starting the metering, for example, before using the first timer with the first timing step to measure the pulse time interval. Specifically, this step can be performed when the diaphragm gas meter is turned on. Alternatively, since the corresponding overcurrent threshold, pulse volume equivalent, and equipped timer type are determined when the meter is produced, then this step can be performed before the diaphragm gas meter leaves the factory, and the above results are pre-stored in the diaphragm gas meter, and the above calculated data can be directly obtained during subsequent use.

[0054] Specifically, the pulse time interval corresponding to the overcurrent threshold is: pulse volume equivalent / overcurrent threshold. It should be noted that when the units of the data used in the calculation process are inconsistent, unit conversion is required. For example, when the unit of the overcurrent threshold (denoted as Q) is m³ / h, the unit of the pulse volume equivalent (denoted as Vc) is dm³ or L, and the pulse time interval threshold T1 in seconds is required, T1=3600 / (Q / Vc*1000).

[0055] The first counting threshold CN1 is the result of dividing the pulse time interval corresponding to the overcurrent threshold (i.e., the pulse time interval threshold T1) by the first timing step and rounding up. Exemplarily, when the first timing step is 1s, the first counting threshold CN1 is equal to the value of the pulse time interval threshold T1 rounded up.

[0056] The second counting threshold CN2 is the result of dividing the pulse time interval corresponding to the overcurrent threshold (i.e., the pulse time interval threshold T1) by the second timing step and rounding down. For example, when the second timing step is 10ms, the result of the second counting threshold CN2=T1 / 0.01 is rounded down.

[0057] The continuous overcurrent pulse number threshold N1 can be set to be less than or equal to the result obtained by dividing the detection time limit by the pulse time interval corresponding to the overcurrent threshold (i.e., the pulse time interval threshold T1) and rounding down, that is, N1≤m. Taking the detection time limit as 2min as an example, the result obtained by m=120 / T1 is rounded down. For example, N1=m can be selected.

[0058] S202: Use a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter.

[0059] When the detection starts, the first timer is started to perform detection measurement. For ease of explanation, the count value of the first timer measuring any pulse time interval can be recorded as CV1.

[0060] S203. Determine whether CV1≤CN1. If yes, execute S204; if no, return to execute S202.

[0061] Among them, when CV1≤CN1, that is, when the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first count threshold, it is preliminarily predicted that overcurrent begins to occur, the current pulse can be considered as the first overcurrent pulse, and the number of continuous overcurrent pulses (recorded as N) = 1 is recorded.

[0062] When CV1>CN1, that is, when the count value of the first timer corresponding to the current pulse time interval is greater than the first count threshold, it indicates that no overflow (or large flow) occurs at present, and the first timer can continue to be used to measure the pulse time interval of the diaphragm gas meter.

[0063] S204, N=1.

[0064] Exemplarily, before the second timer with the second timing step is used to measure the subsequent pulse time interval of the diaphragm gas meter, that is, before the second timer is enabled, the number of continuous overcurrent pulses is recorded as 1.

[0065] S205: Use a second timer with a second timing step to measure subsequent pulse time intervals of the diaphragm gas meter.

[0066] Among them, the second timer can be started first, and then the count value obtained by the second timer accurately measuring the subsequent pulse time intervals of the diaphragm gas meter is obtained. It can be understood that the gas equivalent of each pulse volume passing through the diaphragm gas meter is continuously measured; after the second timer is turned on, the first pulse time interval collected is the next pulse time interval continuous with the current pulse time interval. For ease of explanation, the count value of any pulse time interval measured by the second timer can be recorded as CV2.

[0067] S206. Determine whether CV2≤CN2? If yes, execute S207; if no, execute S210.

[0068] Among them, this judgment is performed at each subsequent pulse time interval of the diaphragm gas meter measured by the second timer. When CV2≤CN2, that is, when the count value of the second timer corresponding to the pulse time interval is less than or equal to the second count threshold, it indicates that overcurrent occurs within the pulse time interval, and the number of continuous overcurrent pulses N can be increased by 1. When CV2>CN2, that is, when the count value of the second timer corresponding to the pulse time interval is greater than the second count threshold, it indicates that overcurrent does not occur within the pulse time interval, or in other words, the currently received pulse does not belong to an overcurrent pulse, and the previous overcurrent prediction result may be a misjudgment. At this time, the number of continuous overcurrent pulses N can be cleared, and the next pulse time interval is switched to be measured by the first timer.

[0069] S207, N=N+1.

[0070] S208. Determine whether N=N1. If so, execute S209; if not, return to execute S205.

[0071] When N=N1, that is, when the number of continuous overcurrent pulses reaches the continuous overcurrent pulse number threshold, it is confirmed that an overcurrent abnormality occurs. When N≠N1, that is, when the number of continuous overcurrent pulses does not reach the continuous overcurrent pulse number threshold, and CV2≤CN2 is still satisfied at this time, the second timer can continue to be used for measurement.

[0072] S209, confirming that an overcurrent abnormality occurs, generating an overcurrent alarm signal, and controlling the valve to close.

[0073] Among them, the overcurrent alarm signal can control the alarm module to issue an overcurrent alarm; control the valve to close, that is, close the valve, which can cut off abnormal gas consumption.

[0074] S210: Turn off the second timer and clear N to zero.

[0075] After completing this step, the process may return to the step of using a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter, that is, return to S202.

[0076] This embodiment implements the complete process of gas overflow detection through S201-S210, and can realize overflow detection in a timely and accurate manner.

[0077] The method is described in detail below in conjunction with a specific embodiment.

[0078] Assume that the first timing step is 1s, the second timing step is 10ms, the detection time limit is 2min, the gas meter specification is G2.5, the overcurrent threshold Q is 4.8m³ / h, the pulse equivalent Vc is 10dm³, then when the gas is flowing according to the overcurrent threshold of 4.8m³ / h, the corresponding pulse time interval T1=3600 / (4.8 / 10*1000)=7.50s, corresponding to the first counting threshold CN1=8 (T1 rounded up), the second counting threshold CN2=T1 / 0.01=750 (rounded down), corresponding to the upper limit of the number of detections within 2min m=120 / 7.5=16 (rounded down), and the continuous overcurrent pulse number threshold N1=m. When the detection starts, the pulse time interval is counted based on the first timer second interrupt. When it is detected that CV1≤CN1 (value is 8) of the first timer, it is preliminarily predicted that overcurrent begins to occur and the current pulse is the first overcurrent pulse (the number of continuous overcurrent pulses N=1). At this time, the second timer is started to accurately calculate the next pulse time interval with 10ms interrupt count to accurately determine whether the next pulse is an overcurrent pulse. Among them, when CV2≤CN2 (value is 750) of the second timer, it is determined to be an overcurrent pulse, and the number of continuous overcurrent pulses N is increased by 1. When the number of continuous overcurrent pulses N reaches N1=16, it is determined to be an overcurrent abnormality, an overcurrent alarm is issued, and the valve closing action is executed to cut off the abnormal gas use.

[0079] In summary, the embodiment of the present invention provides a complete process of overcurrent detection + alarm and action of a diaphragm gas meter. The design concept is: during normal gas flow, the pulse time interval between two adjacent pulses is first measured based on the first timer, and it is roughly predicted whether the current pulse is an overcurrent pulse. If so, the second timer is enabled to accurately calculate the pulse time interval between two subsequent adjacent pulses, and accurately determine whether each subsequent pulse is an overcurrent pulse. When the number of consecutive overcurrent pulses is greater than or equal to the threshold of the number of consecutive overcurrent pulses, an overcurrent alarm and a valve closing action are triggered to achieve abnormal gas use control. When an overcurrent alarm occurs, the second timer is turned off and the first timer is used again to reduce power consumption. Therefore, the embodiment of the present invention can take into account the requirements of the electronic intelligent diaphragm gas meter for low power consumption, accurately detect the occurrence of overcurrent, and accurately implement the alarm valve closing within the specified detection time limit, thereby achieving timely overcurrent detection and abnormal control.

[0080] An embodiment of the present invention further provides a diaphragm gas meter, including a controller, for executing the gas overflow detection method provided by any embodiment of the present invention, and having corresponding beneficial effects.

[0081] Exemplarily, a first timer and a second timer are provided in the controller. A processor may also be provided in the controller, connected to the first timer and the second timer, respectively. As the main data processing part in the controller, the processor may be used to obtain the count value of the first timer and the count value of the second timer, and perform relevant calculations in each step of overcurrent detection. In addition, the diaphragm gas meter may also include an alarm module and a valve. The controller may be used to transmit an overcurrent alarm signal to the alarm module when an overcurrent anomaly is confirmed to occur, so as to control the alarm module to issue an overcurrent alarm; and the controller may be used to control the valve to close when an overcurrent anomaly is confirmed to occur, so as to cut off abnormal gas use. Exemplarily, the controller may be a single-chip microcomputer.

[0082] It is understandable that the above controller, alarm module and valve can be integrated into the electrical part of the diaphragm gas meter; the diaphragm gas meter can also include a mechanical detection part and a conversion part. The diaphragm in the mechanical detection part is used to reciprocate during the gas flow process. When the gas volume passing through the gas meter reaches the pulse volume equivalent, the diaphragm completes a cycle of movement. The conversion part is used to provide a pulse to the controller every time the diaphragm completes a cycle of movement. The controller records the pulse time interval between each two adjacent pulses to achieve gas flow rate monitoring.

[0083] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0084] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas overflow detection method, characterized in that: include: Measuring the pulse time interval of the diaphragm gas meter using a first timer having a first timing step length; When the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first count threshold, a second timer with a second timing step is used to measure the subsequent pulse time interval of the diaphragm gas meter; wherein the first counting threshold is the count value corresponding to the pulse time interval corresponding to the overcurrent threshold when the first timing step is used for measurement; the second timing step is less than the first timing step; When the count values ​​of the second timer in a consecutive preset number of pulse time intervals are all less than or equal to the second count threshold, an overcurrent abnormality is confirmed; wherein, the second count threshold is the count value corresponding to the pulse time interval corresponding to the overcurrent threshold when the second timing step is used for measurement; the preset number is less than the number of complete pulse time intervals that pass within the detection time limit when the gas is leaking at the overcurrent threshold; the preset number is any positive integer between 1 and m-1, m is the number of complete pulse time intervals that pass within the detection time limit when the gas is leaking at the overcurrent threshold; m is obtained by rounding down the ratio of the detection time limit to the pulse time interval threshold; the pulse time interval threshold is the pulse time interval corresponding to the overcurrent threshold.

2. The gas overflow detection method according to claim 1, characterized in that: The first counting threshold is a result obtained by dividing the pulse time interval corresponding to the overcurrent threshold by the first timing step and rounding up; And / or, the second counting threshold is a result obtained by dividing the pulse time interval corresponding to the overcurrent threshold by the second timing step and rounding down.

3. The gas overflow detection method according to claim 1, characterized in that: The second timing step is 0.5%-5% of the first timing step.

4. The gas over-flow detection method according to claim 3, characterized in that: The first timing step is 1 second, and the second timing step is 10 milliseconds.

5. The gas overflow detection method according to claim 1, characterized in that: Also includes: When the count value of the first timer corresponding to the current pulse time interval is greater than the first count threshold, the first timer continues to be used to measure the pulse time interval of the diaphragm gas meter.

6. The gas over-flow detection method according to claim 1, characterized in that: Before using a second timer with a second timing step to measure the subsequent pulse time interval of the diaphragm gas meter, the method further includes: The number of continuous overcurrent pulses is recorded as 1; When the second timer is used to measure each of the subsequent pulse time intervals of the diaphragm gas meter, the method further includes: When the count value of the second timer corresponding to the pulse time interval is less than or equal to the second count threshold, the number of continuous overcurrent pulses is increased by 1; When the count value of the second timer corresponding to the pulse time interval is greater than the second count threshold, the number of continuous overcurrent pulses is reset to zero, and the process returns to the step of using the first timer with the first timing step to measure the pulse time interval of the diaphragm gas meter; Wherein, when the number of continuous overcurrent pulses reaches the continuous overcurrent pulse number threshold, it is confirmed that an overcurrent abnormality occurs; after confirming that an overcurrent abnormality occurs, it also includes: The number of the continuous overcurrent pulses is cleared, and the process returns to the step of using a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter.

7. The gas over-current detection method according to claim 6, characterized in that: The continuous over-current pulse number threshold is less than or equal to the detection time limit divided by the pulse time interval corresponding to the over-current threshold and rounded down.

8. The gas overflow detection method according to any one of claims 1 to 7, characterized in that: When the first timer is used to measure the pulse time interval of the diaphragm gas meter, the second timer is turned off.

9. The gas overflow detection method according to any one of claims 1 to 7, characterized in that: While confirming the overcurrent abnormality, it also includes: Generate an over-current alarm signal and control the valve to close.

10. A membrane gas meter, characterized in that: include: A controller, wherein a first timer and a second timer are provided in the controller; the controller is used to execute the gas overflow detection method according to any one of claims 1-9.

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