JP4060719B2 - Gas meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas meter, and more particularly to a technique for preventing erroneous determination based on detection of abnormality of the gas meter.
[0002]
[Prior art]
Conventionally, for example, as disclosed in Japanese Patent No. 161389, a gas meter is known that measures the amount of gas used and detects and notifies a gas leak. In such a conventional gas meter, a small amount of gas continuously flows for a long time into a gas pipe (hereinafter referred to as “inner pipe”) from the gas meter to a consumer gas appliance, for example, 3 liters / hour. When the flow sensor detects that the gas has flowed continuously for 30 days, it is determined that a gas leak has occurred.
[0003]
However, since the conventional gas meter detects a small flow rate gas, it takes a long time to output a flow rate signal from the flow rate sensor. As a result, even if there is a short period of time during which the gas does not flow, if a large flow rate of gas flows after a short period of time, it will be erroneously determined that a small flow rate of gas will continue to be averaged. There was a drawback of end. Therefore, the conventional gas meter employs an instantaneous flow rate sensor that can measure the instantaneous flow rate as a flow rate sensor, and measures are taken to detect a short time flow stop.
[0004]
[Problems to be solved by the invention]
However, in a flow sensor that outputs the flow rate as an analog signal, although rare, the sensor and the amplifier circuit that amplifies the analog signal from this sensor change over time due to the influence of the external environment, and an analog signal indicating a zero flow rate value is generated. May change. When such a state occurs, there is a problem that an analog signal is output even though the predetermined flow rate indicating that the flow rate is actually reached has not been reached, and it is erroneously determined that there is a flow rate.
[0005]
The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a gas meter capable of improving the erroneous determination based on the secular change of the flow sensor while preventing the erroneous determination due to the short time flow stop.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is provided in the middle of a gas flow path, detects a flow rate of gas flowing through the gas flow path and outputs it as a flow rate signal, and the gas flow path. A pressure sensor that detects a pressure in the gas flow path and outputs it as a pressure signal, and is provided upstream of the flow rate sensor and the pressure sensor in the gas flow path. A shut-off valve that shuts off the gas, and when it is determined that there is an inner pipe leak based on a flow signal from the flow sensor, the shut-off valve is driven to shut off the gas flow path, and a pressure signal from the pressure sensor There is judged whether the flow signal from the flow sensor when no indicate a drop in pressure indicates a zero flow rate value, and a control unit for checking the presence or absence of abnormality of the flow rate sensor, the control Part of the flow rate sensor The flow rate signal from the. If not a zero flow rate value, characterized in that to open the gas flow path by driving the shut-off valve.
[0007]
According to the invention of claim 1, the control unit determines that there is an inner pipe leak when the flow rate signal from the flow rate sensor is greater than a predetermined determination value and continues for a predetermined time or more, and Drive to shut off the gas flow path. Since the flow sensor is located on the downstream side of the shut-off valve, when the gas flow is shut off by the shut-off valve, the flow rate flowing into the flow sensor becomes zero. At this time, if the inner pipe leaks, the gas remaining in the blocked inner pipe leaks and the gas pressure decreases. On the other hand, when the gas pressure does not decrease, the flow rate of the flow rate sensor is zero, so that the zero flow rate value can be determined. In this case, when the flow rate value based on the flow rate signal from the flow rate sensor does not become zero, it is determined that there is an abnormality in the flow rate sensor. For this reason, since an abnormality due to a secular change or the like of the flow sensor can be determined, it is possible to improve erroneous determination of inner pipe leakage. In addition, when there is a possibility that the detected leak in the inner pipe is an erroneous determination, the shut-off valve is automatically opened, preventing a situation in which the customer cannot use gas due to an erroneous determination. it can.
[0010]
According to a second aspect of the present invention, in the gas meter according to the first aspect of the present invention, the gas meter includes a seismic sensor that detects the applied vibration and outputs the seismic signal, and the control unit is configured to determine the leakage of the inner pipe during the determination of the inner pipe leakage. When an abnormality is detected based on at least one of a flow signal from a flow sensor, a pressure signal from the pressure sensor, and a seismic signal from the seismic sensor, the shut-off valve is driven to open the gas flow path. It shuts off, it is determined whether the said flow signal from the said flow sensor has shown the zero flow value, and the presence or absence of the abnormality of the said flow sensor is test | inspected.
[0011]
According to the second aspect of the present invention, before determining that it is the above-mentioned inner pipe leakage, the determination of the inner pipe leakage in which the flow rate signal from the flow sensor is larger than a predetermined determination value and continues for a predetermined time or more. In addition, when an abnormality is detected based on at least one of the flow signal, pressure signal, and seismic signal, the shutoff valve shuts off the gas flow path and whether the flow signal from the flow sensor indicates a zero flow value Thus, the presence or absence of abnormality of the flow sensor is inspected, so that the zero flow rate value can be determined before the determination of the inner pipe leakage. For this reason, it is possible to prevent erroneous determination of inner pipe leakage.
[0012]
According to a third aspect of the present invention, in the gas meter according to the first aspect, the control unit drives the shut-off valve when detecting an abnormality other than the inner pipe leakage when the inner pipe leakage is not being determined. The gas flow path is shut off, it is determined whether the flow rate signal from the flow rate sensor indicates a zero flow rate value, and the presence or absence of abnormality of the flow rate sensor is inspected. According to the invention of claim 3 , it is possible to detect when the flow rate signal is shifted in the minus direction, and it is possible to prevent erroneous determination of inner pipe leakage.
[0013]
The invention according to claim 4 includes a notifying unit for notifying that the gas meter according to any one of claims 1 to 3 is notified when the control unit detects leakage of the inner pipe. It is characterized by that. According to the invention of claim 4, an abnormal state such as leakage of the inner pipe is not left unattended.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding parts as those of the conventional gas meter are denoted by the same reference numerals as those used in the column of the prior art.
[0015]
FIG. 1 is a diagram schematically showing the structure of a gas meter according to an embodiment of the present invention. This gas meter guides gas supplied from the outside to the inside from the gas inlet 1 and sends it out from the gas outlet 5 to the gas equipment (not shown) of the customer via the gas flow path 3 formed inside. It is configured.
[0016]
The gas flow path 3 is provided with a shut-off valve 50, an instantaneous flow rate sensor 21, and a pressure sensor 30 in that order from the upstream side. A control circuit 10 is provided inside the gas meter, and a shut-off valve 50, an instantaneous flow rate sensor 21, and a pressure sensor 30 are connected to the control circuit 10. The control circuit 10 is connected to a seismic sensor 40 provided at a predetermined portion of the gas meter and a display unit 61 provided on the front surface of the gas meter.
[0017]
FIG. 2 is a block diagram showing an electrical configuration of the gas meter according to the embodiment of the present invention. The gas meter includes a flow sensor 20, a pressure sensor 30, a seismic sensor 40, a shutoff valve 50, and a notification unit 60 connected to the control circuit 10.
[0018]
The control circuit 10 is composed of, for example, a microcomputer and its peripheral circuits, and controls the entire gas meter. When the control circuit 10 monitors the flow signal from the flow sensor 20, the pressure signal from the pressure sensor 30, and the seismic signal from the seismic sensor 40, and determines that an abnormality has occurred based on these signals, A control signal is sent to the shut-off valve 50 to shut off the gas flow path, and a control signal is sent to the reporting unit 60 to notify the customer and the center to that effect. The processing performed by the control circuit 10 will be described in detail later.
[0019]
The flow rate sensor 20 detects the flow rate of the gas flowing through the gas flow path 3 and sends it to the control circuit 10 as a flow rate signal. The flow sensor 20 includes an instantaneous flow sensor 21, an amplifier circuit 22, and an analog-digital conversion circuit (hereinafter referred to as “A / D conversion circuit”) 23. The flow rate sensor 20 is provided for integrating the amount of gas used and for stopping gas supply when the gas flow rate becomes abnormal due to gas leakage or the like.
[0020]
The instantaneous flow rate sensor 21 is composed of a flow sensor or the like, periodically detects the instantaneous flow rate of gas in the gas flow path 3, and outputs the detection result as an analog signal. For this reason, it is possible to detect a short time flow stop. An analog signal from the instantaneous flow rate sensor 21 is sent to the amplifier circuit 22.
[0021]
The amplification circuit 22 amplifies the analog signal from the instantaneous flow rate sensor 21 so as to have an appropriate magnitude, and sends the amplified signal to the A / D conversion circuit 22. The A / D conversion circuit 22 converts the received analog signal into a digital signal and sends it to the control circuit 10 as a flow rate signal. Based on this flow rate signal, the control circuit 10 determines the presence or absence of an inner pipe leak or the presence or absence of an abnormality in the flow rate sensor 20, as will be described later.
[0022]
The pressure sensor 30 detects the pressure of the gas in the gas flow path and sends it to the control circuit 10 as a pressure signal. In a normal state where the shut-off valve 50 is open, the pressure sensor 30 detects the gas pressure in the gas flow path 3 from the outside to the consumer's gas equipment, and in a state where the shut-off valve 50 is closed, The pressure of the gas in the gas flow path from the gas meter to the customer's gas equipment is detected. The pressure sensor 30 is provided to stop the supply of gas when the gas pressure becomes abnormal due to gas leakage or the like.
[0023]
The seismic sensor 40 detects vibration applied to the gas meter and sends it to the control circuit 10 as a seismic signal. The seismic sensor 40 is provided to stop the gas supply when it is not appropriate to supply the gas due to an earthquake or the like.
[0024]
The shut-off valve 50 is provided in the middle of the gas flow path 3 in the gas meter and upstream of the instantaneous flow rate sensor 21. The shut-off valve 50 is opened / closed according to a control signal from the control circuit 10 and is used to control the shut-off and passage of gas in the gas flow path.
[0025]
The reporting unit 60 includes a display unit 61 and a communication circuit 62. The display unit 61 includes a display member such as an LED (light emitting diode) or an LCD (liquid crystal display element). In response to a control signal from the control circuit 10, the display unit 61 displays a message to that effect when an abnormality such as gas leakage occurs.
[0026]
The communication circuit 62 is connected to the center via a wired or wireless line (not shown). In response to a control signal from the control circuit 10, the communication circuit 62 normally sends an accumulated amount of gas used by a consumer to the center, and when an abnormality such as gas leakage occurs, a message indicating that fact is sent to the center. Send to.
[0027]
Next, the operation of the gas meter according to the embodiment of the present invention configured as described above will be described with reference to the flowcharts shown in FIGS.
[0028]
(First embodiment)
The gas meter according to the first embodiment of the present invention is configured to inspect whether there is an abnormality in the flow sensor 20 when an inner pipe leak occurs.
[0029]
FIG. 3 is a flowchart showing processing in the control circuit of the gas meter according to the first embodiment of the present invention.
[0030]
In this gas meter, when the flow rate signal from the flow rate sensor 20 is larger than a predetermined determination value and the flow rate signal continues for a predetermined time, it is recognized that an inner pipe leak has occurred.
[0031]
Although omitted in FIG. 3, prior to executing the following processing, a timer (not shown) provided in the control circuit 10 for measuring a duration time for determining inner pipe leakage is as follows. It shall be cleared to zero.
[0032]
First, the flow sensor 20 periodically detects (measures) the instantaneous flow rate of gas in the gas flow path and sends it to the control circuit 10 as a flow rate signal. The control circuit 10 is activated by receiving the flow rate signal (step S1). When activated, the control circuit 10 performs flow rate value determination (step S2). That is, the control circuit 10 determines whether or not the flow value corresponding to the flow signal from the flow sensor 20 is greater than a predetermined determination value. When it is determined that the flow rate value is smaller than the predetermined determination value, it is recognized that there is no inner pipe leakage, and the process is terminated (step S5).
[0033]
On the other hand, if it is determined in step S2 that the flow rate value is greater than the predetermined determination value, the timer is counted up (step S3). Then, the duration time is determined (step S4). That is, it is determined whether or not the duration time counted up by the timer has reached a predetermined value.
[0034]
Here, when it is determined that the duration time is smaller than the predetermined value, it is recognized that the inner pipe leakage is being determined, and the process is terminated (step S7). On the other hand, if it is determined that the duration time is greater than the predetermined value, it is recognized that a constant flow rate of gas has flowed continuously for a long period of time, and it is tentatively determined that an inner pipe leak has occurred.
[0035]
Then, the gas flow path 3 is shut off and notified (step S6). Specifically, the control circuit 10 sends a control signal indicating that an inner pipe leak has occurred to the shutoff valve 50, the display unit 61, and the communication circuit 62. Thereby, the shut-off valve 50 closes the gas flow path 3 to shut off the gas flow. In addition, the display unit 61 displays a message that an inner pipe leakage has occurred. Further, the communication circuit 62 transmits a message indicating that the inner pipe leakage has occurred to a center (not shown). Thereby, it is possible to prevent an abnormal state such as occurrence of an inner pipe leakage from being left unattended.
[0036]
Next, pressure determination is performed (step S8). That is, the control circuit 10 determines whether or not the pressure is lower than the pressure of the gas flow path 3 before closing the shutoff valve 50 by detecting the pressure signal from the pressure sensor 30. If it is determined that the pressure has decreased, it is recognized that an inner pipe leakage has occurred, and the process is terminated (step S10).
[0037]
On the other hand, when it is determined in step S8 that the pressure has not decreased (that is, when the pressure is constant), zero flow value determination is performed (step S9). That is, the control circuit 10 determines whether or not the flow value based on the flow signal from the flow sensor 20 indicates a zero flow value. Here, when the flow rate value indicates the zero flow rate value, the control circuit 10 determines that the zero flow rate value is normal and there is a small amount of leakage that cannot be determined by the pressure sensor 30, and the inner pipe leakage occurs. The process is terminated (step S10).
[0038]
On the other hand, in step S9, when the flow rate value does not indicate the zero flow rate value, it is determined that the zero flow rate value is abnormal, and shut-off and notification are performed (step S11). Specifically, when the input digital flow rate value does not become zero, the control circuit 10 determines that there is an abnormality somewhere between the flow rate sensor 20 and the A / D conversion circuit 23 and detects the detected flow rate. It is determined that there is a possibility that the pipe leakage is an erroneous determination, and a control signal indicating that the zero flow rate value is abnormal is sent to the shutoff valve 50, the display unit 61, and the communication circuit 62. Thereby, since the shut-off valve 50 opens the gas flow path 3 and flows gas, it can prevent that the situation where a consumer cannot use gas by misjudgment generate | occur | produces. Further, the display unit 61 displays a message indicating that the zero flow rate value is abnormal, and the communication circuit 62 transmits a message indicating that the zero flow rate value is abnormal to the center. Will not be left alone.
[0039]
Here, the difference between the conventional gas meter and the gas meter according to the first embodiment of the present invention will be described. The conventional gas meter performs only the processes of steps S1 to S6 shown in FIG. In other words, when it is determined that a constant flow rate of gas has flowed for a long period of time, the gas flow path is shut off and notification is made. For this reason, even if the zero flow rate value becomes abnormal due to aging of the flow sensor 20 or the like, it is erroneously determined that an inner pipe leakage has occurred, and the gas flow path is shut off and notified.
[0040]
On the other hand, in the gas meter according to the first embodiment of the present invention, the zero flow rate value becomes abnormal due to aging of the flow rate sensor 20 or the like by further executing the processing of steps S7 to S11 shown in FIG. In the event of a failure, the gas flow path 3 is unblocked, and a message to that effect is sent to the center. Accordingly, it is not erroneously determined that the inner pipe leakage has occurred, and a situation in which the gas flow path is blocked due to this erroneous determination and the customer cannot use the gas device can be avoided.
[0041]
(Second Embodiment)
In addition to the function of the gas meter according to the first embodiment, the gas meter according to the second embodiment of the present invention detects an abnormality of the flow sensor 20 when another abnormality occurs during the determination of the inner pipe leakage. The presence or absence is inspected. In the following description, the same reference numerals as those used in the processing of the gas meter according to the first embodiment are attached to the steps for performing the same processing as that of the gas meter according to the first embodiment.
[0042]
In this gas meter, the process shown in the flowchart of FIG. 4 is executed following step S7 shown in FIG. That is, in step S4 shown in FIG. 3, when it is determined that the duration is smaller than the predetermined value, it is recognized that the inner pipe leakage is being determined, and the processing of the gas meter according to the second embodiment is performed. Start (step S12).
[0043]
In this process, first, it is determined whether there is another abnormality (step S13). Here, the other abnormality refers to a case where at least one of the flow signal from the flow sensor 20, the pressure signal from the pressure sensor 30, and the seismic signal from the seismic sensor 40 is out of the normal value. Here, when it is determined that there is no other abnormality, it is recognized that the inner pipe leakage is being determined, and the process ends (step S15).
[0044]
On the other hand, if it is determined in step S13 that there is another abnormality, the gas flow path 3 is blocked and notified (step S14). Specifically, the control circuit 10 sends a control signal indicating that another abnormality has occurred to the shutoff valve 50, the display unit 61, and the communication circuit 62. Thereby, the shut-off valve 50 closes the gas flow path 3 to shut off the gas flow. The display unit 61 displays a message indicating that another abnormality has occurred. Furthermore, the communication circuit 62 transmits a message indicating that another abnormality has occurred to the center.
[0045]
Next, pressure determination is performed (step S8). That is, the control circuit 10 determines whether or not the pressure is lower than the pressure of the gas flow path 3 before closing the shutoff valve 50 by detecting the pressure signal from the pressure sensor 30. If it is determined that the pressure has decreased, it is recognized that an inner pipe leakage has occurred, and the process is terminated (step S16).
[0046]
On the other hand, if it is determined in step S8 that the pressure has not decreased, a zero flow rate value determination is performed (step S9). That is, the control circuit 10 determines whether or not the flow value based on the flow signal from the flow sensor 20 indicates a zero flow value. Here, when the flow rate value indicates the zero flow rate value, the control circuit 10 determines that the zero flow rate value is normal and there is a small amount of leakage that cannot be determined by the pressure sensor 30, and the inner pipe leakage occurs. The process is terminated (step S16).
[0047]
On the other hand, if the flow rate value does not indicate the zero flow rate value in step S9, it is determined that the zero flow rate value is abnormal, and a notification is made (step S17). Specifically, the control circuit 10 sends a control signal indicating that the zero flow rate value is abnormal to the display unit 61 and the communication circuit 62. As a result, the display unit 61 displays a message indicating that the zero flow rate value is abnormal. Further, the communication circuit 62 transmits a message indicating that the zero flow rate value is abnormal to the center. In this case, the shutoff valve 50 is not opened, and the gas flow path remains shut off.
[0048]
As described above, according to the gas meter according to the second embodiment, it is possible to determine the accuracy of the flow rate sensor 20 if the inner pipe leakage is being determined. As a result, the zero flow rate value can be inspected before determining that the inner pipe leakage has occurred, and erroneous determination of the inner pipe leakage can be prevented.
[0049]
(Third embodiment)
In addition to the function of the gas meter according to the first or second embodiment, the gas meter according to the third embodiment of the present invention has a flow rate sensor 20 when another abnormality occurs when it is not determined that the inner pipe leaks. This is to check for the presence or absence of abnormalities. In the following, the same reference numerals as those used in the processing of the gas meter according to the first and second embodiments are attached to the steps for performing the same processing as those of the gas meter according to the first and second embodiments. I will explain.
[0050]
In this gas meter, the processing shown in the flowchart of FIG. 5 is executed following step S5 shown in FIG. That is, when it is determined in step S2 shown in FIG. 3 that the flow rate value is smaller than the predetermined determination value, it is recognized that there is no inner pipe leakage, and the processing of the gas meter according to the third embodiment is performed. Is started (step S18).
[0051]
In this process, it is first determined whether there is any other abnormality (step S19). Here, the other abnormality refers to a case where at least one of the flow signal from the flow sensor 20, the pressure signal from the pressure sensor 30, and the seismic signal from the seismic sensor 40 is out of the normal value. Here, if it is determined that there is no other abnormality, it is recognized that there is no inner pipe leakage, and the process ends (step S21).
[0052]
On the other hand, when it is determined in step S19 that there is another abnormality, the gas flow path 3 is shut off and notified (step S20). Specifically, the control circuit 10 sends a control signal indicating that another abnormality has occurred to the shutoff valve 50, the display unit 61, and the communication circuit 62. Thereby, the shut-off valve 50 closes the gas flow path 3 to shut off the gas flow. The display unit 61 displays a message indicating that another abnormality has occurred. Furthermore, the communication circuit 62 transmits a message indicating that another abnormality has occurred to the center.
[0053]
Next, pressure determination is performed (step S8). That is, the control circuit 10 determines whether or not the pressure is lower than the pressure of the gas flow path 3 before closing the shutoff valve 50 by detecting the pressure signal from the pressure sensor 30. If it is determined that the pressure has decreased, it is recognized that an inner pipe leakage has occurred, and the process is terminated (step S22).
[0054]
On the other hand, if it is determined in step S8 that the pressure has not decreased, zero flow value determination is performed (step S9). That is, the control circuit 10 determines whether or not the flow value based on the flow signal from the flow sensor 20 indicates a zero flow value. Here, when the flow rate value indicates the zero flow rate value, the control circuit 10 determines that the zero flow rate value is normal and there is a small amount of leakage that cannot be determined by the pressure sensor 30, and the inner pipe leakage occurs. The process is terminated (step S22).
[0055]
On the other hand, if the flow rate value does not indicate the zero flow rate value in step S9, it is determined that the zero flow rate value is abnormal, and a notification is made (step S17). Specifically, the control circuit 10 sends a control signal indicating that the zero flow rate value is abnormal to the display unit 61 and the communication circuit 62. As a result, the display unit 61 displays a message indicating that the zero flow rate value is abnormal. Further, the communication circuit 62 transmits a message indicating that the zero flow rate value is abnormal to the center. In this case, the shutoff valve 50 is not opened, and the gas flow path remains shut off.
[0056]
As described above, according to the gas meter according to the third embodiment, the accuracy of the flow sensor 20 can be determined when the determination of the inner pipe leakage is not in progress. As a result, the zero flow rate value can be inspected before the determination of the inner pipe leakage, and the erroneous determination of the inner pipe leakage can be prevented. Further, detection can be performed when the flow rate signal is shifted in the minus direction, and erroneous determination of inner pipe leakage can be prevented.
[0057]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a gas meter capable of improving the erroneous determination based on the secular change of the flow rate sensor while preventing the erroneous determination due to the short time flow stop.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing the structure of a gas meter according to first to third embodiments of the present invention.
FIG. 2 is a block diagram showing an electrical configuration of the gas meter according to the first to third embodiments of the present invention.
FIG. 3 is a flowchart for explaining the operation of the gas meter according to the first embodiment of the present invention.
FIG. 4 is a flowchart for explaining the operation of the gas meter according to the second embodiment of the present invention.
FIG. 5 is a flowchart for explaining the operation of a gas meter according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas inflow port 3 Gas flow path 5 Gas outflow port 10 Control circuit 20 Flow rate sensor 21 Instantaneous flow rate sensor 22 Amplification circuit 23 A / D conversion circuit 30 Pressure sensor 40 Seismic sensor 50 Shut-off valve 60 Notification unit 61 Display unit 62 Communication circuit

Claims (4)

A flow rate sensor that is provided in the middle of the gas flow path and detects the flow rate of the gas flowing through the gas flow path and outputs it as a flow rate signal;
A pressure sensor provided in the middle of the gas flow path for detecting the pressure in the gas flow path and outputting it as a pressure signal;
A shutoff valve provided on the upstream side of the flow rate sensor and the pressure sensor in the gas flow path, and shuts off the gas flow path;
When it is determined that there is an inner pipe leak based on the flow signal from the flow sensor, the shutoff valve is driven to shut off the gas flow path, and the pressure signal from the pressure sensor indicates a decrease in pressure. If there is not, it is determined whether or not the flow signal from the flow sensor indicates a zero flow value, and a control unit that checks whether the flow sensor is abnormal,
Equipped with a,
The control unit opens the gas flow path by driving the shut-off valve when the flow signal from the flow sensor does not indicate a zero flow value .   A seismic sensor that detects the applied vibration and outputs the seismic signal as a seismic signal, and the control unit detects a flow signal from the flow sensor, a pressure signal from the pressure sensor, and When an abnormality is detected based on at least one of the seismic signals from the seismic sensor, the shutoff valve is driven to shut off the gas flow path, and the flow rate signal from the flow rate sensor is a zero flow rate value. The gas meter according to claim 1, wherein it is determined whether or not the flow sensor is abnormal.   The control unit drives the shut-off valve to shut off the gas flow path when the abnormality other than the inner pipe leak is detected when the inner pipe leak is not being determined, and the flow rate from the flow sensor The gas meter according to claim 1, wherein it is determined whether or not the signal indicates a zero flow rate value, and whether or not the flow sensor is abnormal is inspected. The gas meter according to any one of claims 1 to 3 , further comprising a reporting unit that reports that when the control unit detects leakage of an inner pipe.

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