JP2002188948A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas meter capable of detecting early an abnormal load applied to a sliding part such as a valve or the like causing malfunction of a gas meter body when foreign matter enters the gas meter body to increase the load. SOLUTION: When a pressure difference operation part 14 operates the pressure difference between a first pressure value detected by a pressure sensor 22a and a second pressure value detected by a pressure sensor 22b, a warning determination part 15 determines whether the pressure difference acquired by the pressure difference operation part 14 exceeds a set value determined beforehand or not, and, when the pressure difference exceeds the set value, a warning part 30 issues a warning for showing abnormality of the gas meter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormal load on a sliding portion which causes immobility of a gas meter body when foreign matter or the like enters the gas meter body, and for measuring a gas flow rate. The present invention relates to a gas meter that can detect an abnormality or the like at an early stage.

[0002]

2. Description of the Related Art A membrane gas meter measures the flow rate of gas by the number of reciprocating movements of a sac membrane. FIG. 7 shows an interlocking and indicating mechanism of a mechanical integrated gas meter in a conventional membrane gas meter. The figure is shown. FIG. 8 shows a structural diagram of a main part of a mechanical integrating gas meter of the membrane gas meter.

[0003] The operation of this mechanical integrating gas meter will be described with reference to Figs. First, when gas is alternately introduced into each room partitioned by the measuring membrane 1, the measuring membrane 1
Reciprocates due to the differential pressure. The reciprocating motion of the measuring membrane 1 is transmitted to the link mechanism 4 via the blade 2 and the blade shaft 3, and the link mechanism 4 rotates the central shaft 5 and switches a gas supply / discharge. Is converted into the rotational movement of the valve 5b.

Next, the rotational movement of the central shaft 5 is transmitted via a gear 9 to an integration counter 11 which performs a mechanical integration display, and the integration counter 11 displays an integrated gas value.

[0005] A magnet 6 having N and S poles is mounted on a disk mounted on the central shaft 5, and the magnet 6 is rotated by the rotation of the central shaft 5. As a result, the reed switch 7 is repeatedly turned on / off, and a pulse corresponding to the gas usage is generated. The magnet 6 and the reed switch 7 constitute a flow sensor 8. Then, the pulse is sent to the integrating unit 12, the integrating unit 12 integrates the pulse from the flow rate sensor 8, and the communication unit 13 transmits the pulse integrated by the integrating unit 12 to an external monitoring center that performs gas meter reading. ing.

[0006]

However, when foreign matter such as drain enters the gas meter, the foreign matter adheres to a sliding portion such as a valve and gradually adheres to the sliding portion. Make a minus. Further, when the load on the sliding portion is increased, the gas meter is immobilized. For this reason, it has been desired to detect an abnormal load on the sliding portion at an early stage, which causes a negative difference in the instrument and a movement of the gas meter.

Further, the measuring membranes 1 provided in the respective rooms A and B reciprocate by repeating the movement shown in FIG. 9 by the pressure generated by gas supply and discharge. During this reciprocation, the pressure acting on the measuring film 1 fluctuates as shown in FIG. 10 due to the reversal of the forming direction of the film and the mechanical loss peculiar to the crank mechanism.

[0008] However, when a mechanical load is applied to the transmission mechanism by the gear due to the entry of scratches or foreign matter, the measuring membrane 1 needs a pressure higher than the normal pressure in order to repeat the reciprocating motion. As shown in FIG. For this reason, measurement abnormality of the gas flow rate may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to prevent a foreign matter or the like from entering a gas meter main body when the gas meter main body is moved. An object of the present invention is to provide a gas meter capable of detecting an abnormal load at an early stage and detecting an abnormal measurement of a gas flow rate at an early stage.

[0010]

In order to achieve the above object, a gas meter according to the first aspect of the present invention alternately supplies gas to each of two rooms separated by a measuring membrane and reciprocates the measuring membrane. In a film-type gas meter, the reciprocating motion of the measuring membrane is converted into a rotating motion of a rotating shaft by a link mechanism, and a gas flow rate is measured by gas flow measuring means based on the rotating momentum of the rotating shaft. And
First and second pressure sensors for detecting the pressure of each room;
Pressure difference calculating means for calculating the pressure difference between the first pressure value detected by the first pressure sensor and the second pressure value detected by the second pressure sensor; Warning determination means for determining whether the pressure difference exceeds a predetermined set value, and warning means for issuing a warning indicating that the gas meter is abnormal when the pressure difference exceeds the set value. It is characterized by the following.

According to the gas meter of the invention of claim 1, the pressure difference calculation means, the pressure of the second pressure value detected by the first pressure value detected by the first pressure sensor of the second pressure sensor When calculating the difference, the warning determining means determines whether the pressure difference obtained by the pressure difference calculating means has exceeded a predetermined set value, and when the pressure difference exceeds the set value, the warning means Issues a warning indicating that is abnormal. Therefore, when a foreign matter such as a drain enters the gas meter main body and the load increases, an abnormal load on a sliding portion such as a valve, which causes immobility of the gas meter main body, can be detected at an early stage.

A gas meter according to a second aspect of the present invention is the first aspect of the invention.
The gas meter according to claim 1, further comprising a flow rate determining unit configured to determine whether there is a gas flow rate based on a signal from the gas flow rate measuring unit. When the time exceeds a predetermined time, the pressure difference is calculated.

According to the gas meter of the present invention, when the flow rate determining means determines whether there is a gas flow rate based on a signal from the gas flow rate measuring means, the pressure difference calculating means determines that the gas flow rate is present. Since the pressure difference is calculated when the elapsed time from the time when the pressure is exceeded exceeds a predetermined time, it is necessary to obtain an accurate pressure difference without being affected even if the pressure difference becomes large at the time of starting the gas meter. Can be.

According to a third aspect of the present invention, the gas meter alternately supplies gas to each of the two rooms separated by the measuring film to reciprocate the measuring film, and the reciprocating motion of the measuring film is rotated by a link mechanism. In a film-type gas meter for measuring the gas flow rate by gas flow rate measuring means based on the rotational momentum of the rotating shaft, the film type gas meter is attached to one of the two rooms and detects the pressure in that room. A pressure sensor, a pressure fluctuation width calculating means for monitoring a pressure value detected by the pressure sensor, and calculating a pressure fluctuation width indicating a difference between an upper limit and a lower limit of the pressure value, and each pressure corresponding to each flow rate. A pressure fluctuation width determination value table that stores the fluctuation width determination value, and a pressure fluctuation width determination value according to the gas flow rate detected by the gas flow rate measuring unit is determined with reference to the pressure fluctuation width determination value table. Pressure fluctuation width determination value determination means, and warning determination means for determining whether the pressure fluctuation width obtained by the pressure fluctuation width calculation means exceeds the pressure fluctuation width determination value obtained by the pressure fluctuation width determination value determination means. And a warning unit for issuing a warning indicating that the measurement of gas is abnormal when the pressure fluctuation width exceeds the pressure fluctuation width determination value.

According to the gas meter of the third aspect of the present invention, the pressure fluctuation width calculating means monitors the pressure value detected by the pressure sensor and calculates the pressure fluctuation width indicating the difference between the upper limit and the lower limit of the pressure value. The pressure fluctuation width determination value determining means refers to the pressure fluctuation width determination value table, determines a pressure fluctuation width determination value corresponding to the gas flow rate detected by the gas flow rate measuring means, and the warning determination means It is determined whether the pressure fluctuation width obtained by the width calculation means exceeds the pressure fluctuation width determination value obtained by the pressure fluctuation width determination value determination means, and the warning means determines that the pressure fluctuation width exceeds the pressure fluctuation width determination value. In this case, a warning indicating that the gas measurement is abnormal is issued. Therefore, it is possible to detect, at an early stage, a measurement abnormality or the like of the gas flow rate that occurs when a load increases due to a foreign substance entering the gas meter body.

According to a fourth aspect of the present invention, in the gas meter according to the third aspect, each of the pressure fluctuation width determination values is determined for each flow rate detected by the pressure sensor for a certain period when the gas meter is installed. It is determined based on the pressure fluctuation width.

According to the gas meter of the present invention, when the gas meter is installed, each pressure fluctuation width determination value is determined based on the pressure fluctuation width for each flow rate detected by the pressure sensor for a fixed period, Since the determined pressure fluctuation width determination value is used in the measurement abnormality determination processing, more accurate measurement abnormality determination processing can be performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a gas meter according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
It is a block diagram of a structure of the gas meter of the embodiment. The gas meter according to the first embodiment is characterized in that, when a foreign substance or the like enters the gas meter main body, an abnormal load on the sliding portion that causes the gas meter main body to move is detected early. The force for rotating the valve is due to the differential pressure between the rooms, and if the load increases due to the attachment of drain or the like to the valve, a large differential pressure is required to rotate the valve. In the first embodiment, an abnormality warning is issued when the differential pressure between the rooms exceeds a set value by using this characteristic.

The gas meter is a membrane type gas meter, and includes a measuring membrane 1, a blade 2, a blade shaft 3, a link mechanism 4, a central shaft 5, a magnet 6, a reed switch 7, an integrating counter 11, a microcomputer 10, and a warning unit 30. Is configured. The microcomputer 10 includes an integrating unit 12, a communication unit 13, a pressure difference calculating unit 14, and a warning determining unit 15.

The flow rate sensor 8 corresponds to the gas flow rate measuring means of the present invention, and comprises a magnet 6 and a reed switch 7, measures the flow rate of the gas flowing through the gas flow path, and accumulates a pulse corresponding to the gas flow rate. 12 is output.

In the configuration shown in FIG. 1, the same portions as those shown in FIGS. 7 and 8 are denoted by the same reference numerals, and description thereof will be omitted.

Each of the chambers 20a and 20b has a gas inlet / outlet 2
1a and 21b are provided, and the metering membrane 1 reciprocates by gas supply and discharge. Each room 20a,
A pressure sensor 22a, 22b for detecting the pressure of each room 20a, 20b is attached to 20b.

The pressure difference calculator 14 calculates a pressure difference between the first pressure value detected by the pressure sensor 22a and the second pressure value detected by the pressure sensor 22b. The warning determination unit 15
It is determined whether or not the pressure difference obtained by the pressure difference calculation unit 14 exceeds a predetermined set value. If the pressure difference exceeds the set value, a warning signal indicating that the gas meter is abnormal is warned. Output to the unit 30. The warning unit 30 issues an abnormality warning based on a warning signal from the warning determination unit 15, and is, for example, a warning buzzer or a display such as a 7-segment display.

Next, the first embodiment of the present invention constructed as described above will be described.
The abnormality detection processing of the gas meter according to the embodiment will be described with reference to the flowchart shown in FIG.

First, the microcomputer 10 determines whether or not there is a gas flow based on a flow detection signal from the flow sensor 8 (step S11). If there is a gas flow, it is determined that there is a gas flow. It is determined whether or not the set time has elapsed from the time when the time has elapsed (step S1).
3). That is, since the pressure difference at the time of starting the gas meter temporarily increases, the calculation of the pressure difference is started after a lapse of a set time after the determination that there is a flow rate.

Next, the pressure difference calculating section 14 detects the pressure sensor 2
When the pressure difference between the first pressure value detected at 2a and the second pressure value detected at the pressure sensor 22b is calculated (Step S
15), the warning determination unit 15 determines whether the pressure difference obtained by the pressure difference calculation unit 14 exceeds a predetermined set value (Step S17).

When the pressure difference exceeds the set value, the alarm determining section 15 outputs a warning signal indicating that the gas meter is abnormal to the warning section 30. An abnormality warning is issued based on the warning signal from (step S19).

As described above, according to the gas meter of the first embodiment, when the pressure difference between the respective rooms exceeds the set value, an abnormality warning is issued. Therefore, when drain or the like enters the gas meter main body and the load increases, an abnormal load on the valve that causes the gas meter main body to move can be detected early. As a result, a quick action can be taken before the gas meter becomes immobile, and inconvenience such as a gas consumer being unable to consume gas can be eliminated.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The gas meter according to the embodiment will be described. FIG. 3 is a configuration block diagram of a gas meter according to the second embodiment of the present invention. The gas meter according to the second embodiment is characterized in that when a foreign substance or the like enters the gas meter main body, an abnormal measurement of the gas flow rate or the like is detected early.

The gas meter is a membrane type gas meter, and includes a measuring membrane 1, a blade 2, a blade shaft 3, a link mechanism 4, a central shaft 5, a magnet 6, a reed switch 7, an integrating counter 11, a microcomputer 10a, and a warning unit 30a. Is configured. The microcomputer 10a is configured to have an integration unit 12, a communication unit 13, a warning determining unit 15a, the pressure variation range determination value determining unit 16, the pressure variation range determination value table 17, the pressure fluctuation width calculating unit 18.

The flow rate sensor 8 corresponds to the gas flow rate measuring means of the present invention, and comprises a magnet 6 and a reed switch 7, measures the flow rate of the gas flowing in the gas flow path, and accumulates a pulse corresponding to the gas flow rate. 12 is output.

In the configuration shown in FIG. 3, the same portions as those shown in FIGS. 7 and 8 are denoted by the same reference numerals, and description thereof will be omitted.

Each of the chambers 20a and 20b has a gas inlet / outlet 2
1a and 21b are provided, and the metering membrane 1 reciprocates by gas supply and discharge. The room 20a is provided with a pressure sensor 22a for detecting the pressure of the room 20a.

As shown in FIG. 4, the pressure fluctuation width judgment value table 17 stores each pressure fluctuation width judgment value corresponding to each flow rate value. Here, the pressure fluctuation range refers to a difference between the lower limit and the upper limit of the pressure value in the room 20.

The pressure fluctuation width determination value determination section 16 refers to the pressure fluctuation width determination value table 17 to determine a pressure fluctuation width determination value corresponding to the gas flow rate detected by the flow sensor 8.
The pressure fluctuation width calculation unit 18 monitors the pressure value detected by the pressure sensor 22a and calculates the pressure fluctuation width.

The warning judging section 15a includes a pressure fluctuation calculating section 1
The pressure fluctuation width obtained in step 8 is a pressure fluctuation width determination value determination unit 16
It is determined whether the pressure fluctuation width exceeds the pressure fluctuation width determination value obtained in step 3. If the pressure fluctuation width exceeds the pressure fluctuation width determination value, a warning signal indicating a gas measurement abnormality is output to the warning unit 3.
0a. The warning unit 30a issues a measurement abnormality warning based on a warning signal from the warning determination unit 15a, and is, for example, a warning buzzer or a display such as a 7-segment display.

Next, the second embodiment of the present invention constructed as described above will be described.
The measurement abnormality process of the gas meter according to the embodiment will be described with reference to the flowchart shown in FIG. First, the flow sensor 8 detects the flow rate of the gas (Step S31).

Next, the pressure fluctuation width determination value determination section 16 refers to the pressure fluctuation width determination value table 17 and
The pressure fluctuation range determination value corresponding to the gas flow rate detected in step (1) is determined (step S33). Then, the pressure fluctuation width calculation unit 1
8 monitors the pressure value detected by the pressure sensor 22a,
The pressure fluctuation width is calculated (step S35).

Next, the warning judging section 15a judges whether the pressure fluctuation width obtained by the pressure fluctuation width calculating section 18 exceeds the pressure fluctuation width judgment value obtained by the pressure fluctuation width judgment value determining section 16. (Step S37).

Here, if the pressure fluctuation width does not exceed the pressure fluctuation width judgment value, the gas meter is normally used (step S39). On the other hand, when the pressure fluctuation width exceeds the pressure fluctuation width determination value, a warning signal indicating that the measurement of the gas is abnormal is output to the warning unit 30a, so that the warning unit 30a issues a warning from the warning determination unit 15a. A measurement abnormality warning is issued based on the signal (step S41).

As described above, according to the gas meter of the second embodiment, when the pressure fluctuation range exceeds the pressure fluctuation range judgment value, that is, when the mechanical mechanism due to the entry of a flaw or foreign matter into the transmission mechanism by the gear, When a target load is applied, a warning is issued, so that a measurement abnormality can be detected at an early stage. Thus, measures can be taken before a measurement error occurs.

The gas meter according to the second embodiment has
The measurement abnormality process may be performed according to the flowchart shown in FIG. This measurement abnormality process will be described with reference to FIG.
First, a gas meter is installed (step S51), and a pressure fluctuation width for each flow rate when the gas is used is learned for a predetermined time by the pressure sensor 22a provided in the gas meter (step S53). Then, based on the learned result, a pressure fluctuation width determination value for each flow rate is determined (Step S
53).

After the learning is completed, the flow sensor 8 detects the gas flow (step S57). Next, the pressure fluctuation width determination value determination unit 16 refers to the pressure fluctuation width determination value table 17 and determines a pressure fluctuation width determination value corresponding to the gas flow rate detected by the flow sensor 8 (step S59). And
The pressure fluctuation width calculating unit 18 monitors the pressure value detected by the pressure sensor 22a and calculates the pressure fluctuation width (Step S).
61).

Next, the warning judgment section 15a judges whether or not the pressure fluctuation width obtained by the pressure fluctuation width calculation section 18 exceeds the pressure fluctuation width judgment value obtained by the pressure fluctuation width judgment value determination section 16. (Step S63).

Here, when the pressure fluctuation width does not exceed the pressure fluctuation width judgment value, the gas meter is normally used (step S65). On the other hand, when the pressure fluctuation width exceeds the pressure fluctuation width determination value, a warning signal indicating that the measurement of the gas is abnormal is output to the warning unit 30a, so that the warning unit 30a issues a warning from the warning determination unit 15a. A measurement abnormality warning is issued based on the signal (step S67).

As described above, since the pressure fluctuation range for each flow rate is learned by the pressure sensor and this learning result is used, a more accurate measurement abnormality determination process can be performed.

In the gas meters of the first and second embodiments, the mechanical integrated display gas meter of the membrane gas meter is exemplified. However, the present invention is not limited to this. It is also applicable to the liquid crystal integrating gas meter inside. In this liquid crystal integrated gas meter,
8 is not provided, and instead of this integration counter 11, an integration display section comprising a liquid crystal display element is provided, and the pulses from the flow rate sensor 8 are integrated by the integration section 12, and the integration section 12 The integrated pulse is displayed on the integration display unit as an integrated gas value.

[0049]

According to the gas meter of the first aspect of the present invention,
The pressure difference calculating means detects the first pressure detected by the first pressure sensor.
When calculating the pressure difference between the pressure value and the second pressure value detected by the second pressure sensor, the warning determination means determines whether the pressure difference obtained by the pressure difference calculation means has exceeded a predetermined set value. The warning means issues a warning indicating that the gas meter is abnormal when the pressure difference exceeds the set value.
Therefore, when a foreign matter such as a drain enters the gas meter main body and the load increases, an abnormal load on a sliding portion such as a valve, which causes immobility of the gas meter main body, can be detected at an early stage.

According to the gas meter of the present invention, when the flow rate determining means determines whether there is a gas flow rate based on a signal from the gas flow rate measuring means, the pressure difference calculating means determines that the gas flow rate is present. Since the pressure difference is calculated when the elapsed time from the time when the pressure is exceeded exceeds a predetermined time, it is necessary to obtain an accurate pressure difference without being affected even if the pressure difference becomes large at the time of starting the gas meter. Can be.

According to the gas meter of the present invention, the pressure fluctuation range calculating means monitors the pressure value detected by the pressure sensor and calculates the pressure fluctuation range indicating the difference between the upper limit and the lower limit of the pressure value. The pressure fluctuation width determination value determining means refers to the pressure fluctuation width determination value table, determines a pressure fluctuation width determination value corresponding to the gas flow rate detected by the gas flow rate measuring means, and the warning determination means It is determined whether the pressure fluctuation width obtained by the width calculation means exceeds the pressure fluctuation width determination value obtained by the pressure fluctuation width determination value determination means, and the warning means determines that the pressure fluctuation width exceeds the pressure fluctuation width determination value. In this case, a warning indicating that the gas measurement is abnormal is issued. Therefore, it is possible to detect, at an early stage, a measurement abnormality or the like of the gas flow rate that occurs when a load increases due to a foreign substance entering the gas meter body.

According to the gas meter of the present invention, when the gas meter is installed, each pressure fluctuation width determination value is determined based on the pressure fluctuation width for each flow rate detected by the pressure sensor for a certain period, Since the determined pressure fluctuation width determination value is used in the measurement abnormality determination processing, more accurate measurement abnormality determination processing can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a gas meter according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an abnormality detection process of the gas meter according to the first embodiment.

FIG. 3 is a configuration block diagram of a gas meter according to a second embodiment.

FIG. 4 is a diagram showing a pressure fluctuation range determination value table.

FIG. 5 is a flowchart illustrating a measurement abnormality detection process of the gas meter according to the second embodiment.

FIG. 6 is a flowchart illustrating a measurement abnormality detection process of a modification of the gas meter according to the second embodiment.

FIG. 7 is an explanatory diagram of an interlocking and indicating mechanism of a mechanical integrating gas meter in a conventional membrane gas meter.

8 is a main part structural diagram of a mechanical integrated gas meter in the membrane gas meter shown in FIG. 7;

FIG. 9 is a reciprocating motion diagram of a measuring membrane of a conventional membrane gas meter.

FIG. 10 is a diagram showing a temporal change in the pressure acting on the measuring membrane of the membrane gas meter in a normal state.

FIG. 11 is a diagram showing a temporal change when the pressure acting on the measuring membrane of the membrane gas meter is abnormal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring membrane 2 Saw blade 3 Blade axis 4 Link mechanism 5 Central axis 6 Magnet 7 Reed switch 8 Flow rate sensor 9 Gear 10 Microcomputer 11 Integration counter 12 Integration section 13 Communication section 14 Pressure difference calculation section 15, 15a Warning determination section 16 Pressure fluctuation width determination value determination unit 17 Pressure fluctuation width determination table 18 Pressure fluctuation width calculation unit 20a, 20b Room 21a, 21b Gas inlet / outlet 22a, 22b Pressure sensor 30, 30b Warning unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01F 15/06 G01F 15/06 F-term (Reference) 2F030 CA01 CB04 CC13 CE02 CE21 CE22 CE23 CE25 CE27 CF11 CF20 2F031 AA01 AE07 AE09 AF04 AF10

Claims (4)

[Claims] 1. A gas is alternately supplied to each of two rooms separated by a measuring membrane to reciprocate the measuring membrane,
In a film-type gas meter that converts the reciprocating motion of the measuring membrane into a rotational motion of a rotating shaft by a link mechanism and measures a gas flow rate by a gas flow rate measuring means based on a rotational momentum of the rotating shaft, each membrane is attached to each of the rooms. First and second pressure sensors for detecting a pressure in a room; and a pressure difference between a first pressure value detected by the first pressure sensor and a second pressure value detected by the second pressure sensor. A pressure difference calculating means for calculating; a warning determining means for determining whether a pressure difference obtained by the pressure difference calculating means exceeds a predetermined set value; and a gas meter when the pressure difference exceeds a set value. A warning unit that issues a warning indicating that the gas is abnormal. 2. The apparatus according to claim 1, further comprising: a flow rate determining unit configured to determine whether there is a gas flow rate based on a signal from the gas flow rate measuring unit. The gas meter according to claim 1, wherein the pressure difference is calculated when a time exceeds a predetermined time. 3. A gas is alternately supplied to each of the two rooms separated by the measuring membrane to reciprocate the measuring membrane,
In a film type gas meter for converting a reciprocating motion of a measuring membrane into a rotational motion of a rotary shaft by a link mechanism and measuring a gas flow rate by a gas flow rate measuring means based on a rotational momentum of the rotary shaft, one of the two rooms And a pressure sensor that detects the pressure in the room and monitors a pressure value detected by the pressure sensor, and calculates a pressure fluctuation width indicating a difference between an upper limit and a lower limit of the pressure value. Means, a pressure fluctuation width determination value table storing each pressure fluctuation width determination value corresponding to each flow rate, and referring to the pressure fluctuation width determination value table, the flow rate of the gas detected by the gas flow rate measurement means is referred to. A pressure fluctuation width determination value determining means for determining a corresponding pressure fluctuation width determination value; and a pressure fluctuation width obtained by the pressure fluctuation width calculation value determining means. Warning judgment means for judging whether the pressure fluctuation range has been exceeded, and warning means for issuing a warning indicating that there is a gas measurement abnormality when the pressure fluctuation width exceeds the pressure fluctuation width judgment value. Characteristic gas meter. 4. The method according to claim 1, wherein each of the pressure fluctuation width determination values is determined based on a pressure fluctuation width for each flow rate detected by the pressure sensor for a certain period when the gas meter is installed. Item 3. The gas meter according to Item 3.