JP2002098567A - Abnormality detection method for gas meter and gas supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality detection method for a gas meter and gas supply enabling enhancement of reliability in decisions related to warning operation. SOLUTION: CPU 12 checks that the absolute value of a difference in a flow rate ΔQS is equivalent to or more than that of reference flow rate QSK (|ΔQS|>=QSK) and then sequentially detects 'first decision shift state' where decision for gas G consumption state shifts from 'no flow rate change' to 'flow rate changed', and next 'second decision shift state' where it shifts from 'flow rate changed' to 'no flow rate change'. At this time, CPU 12 determines that a gas utensil 1 has operated when the difference in flow rate ΔQS varied within forward area during 'first decision shift state'-'flow rate changes'. Thus any operation of gas utensils can precisely be recognized at any time, so reliability in decision regarding warning action performance will be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas meter for measuring the flow rate of a fuel gas and monitoring the safety of a consumer who uses the fuel gas based on the operation state of a gas combustion device, and an abnormality determination for the gas supply. About the method.

[0002]

2. Description of the Related Art In recent years, a gas meter equipped with a membrane type flow meter or the like has been used to measure the consumption (gas flow rate) of household fuel gas (hereinafter simply referred to as "gas") by consumers. It is installed in each home. Recently, in addition to measuring gas flow, the function of monitoring the gas consumption status to ensure the safety of consumers using the gas (security function)
Are also known. This security function is executed by, for example, a microcomputer mounted on the gas meter.

A gas meter having a security function is, for example,
By detecting a change (increase, decrease) in the gas flow rate, the operating state (operating, stop) of the gas appliance (gas burning appliance) is recognized. Then, the gas meter determines whether or not the increase amount of the gas flow rate is equal to or more than a predetermined increase amount (reference flow rate). When the increase amount of the gas flow rate becomes equal to or more than the reference flow rate, in a normal gas use state, It is determined that an excessive gas consumption state that does not occur is detected, and a warning operation such as shutting off gas supply or issuing a warning sound is performed. According to this type of gas meter, an excessive gas supply state in an unforeseen situation with danger to the consumer is detected.

[0004] Here, with reference to Fig. 5, a description will be given of a determination procedure related to execution of a warning operation in a gas meter equipped with a conventional membrane flow meter. FIG. 5 shows an example of a change in the gas flow rate detected by the gas meter. In FIG. 5, the “horizontal axis” represents time T (second), and the “vertical axis” represents the gas flow rate Q (instantaneous flow rate; L ( Liter) / h (hour))
Is represented. FIG. 5 shows, for example, a case where the gas appliance V operates after the time T2 has elapsed while the gas appliance U has been operating before the time T1, and both gas appliances have stopped at the time T4. . A gas meter equipped with a membrane type flow meter cannot, for example, grasp an instantaneous gas flow rate (instantaneous flow rate). Therefore, a flow rate pulse input according to gas consumption is set at a predetermined time interval (about 30 seconds).
Every second) and the flow rate pulse is multiplied by a predetermined pulse rate to calculate the gas flow rate. That is, for example, when the time T2 is reached, the gas flow rate Q1 consumed during the time T1 to T2.
Is calculated, and similarly, the gas flow rates Q2 and Q3 are calculated.
Here, the reason why the counting interval of the flow pulse is set to “about 30 seconds” is that the counting of the flow pulse is not always performed every 30 seconds. This is because the detection is performed until the time of detection.

First, at time T3, the gas meter reads
The flow rate difference between the most recently measured gas flow rate Q2 and the gas flow rate Q1 measured immediately before (ie, the increase in the gas flow rate;
Q2-Q1) and calculate the absolute value of this flow rate difference (| Q2-
Q1 |) is a predetermined multiple (eg, 0.03 times) of the gas flow rate Q1.
0.03Q1) is determined. At this time, the gas meter determines that the absolute value of the flow rate difference is larger than 0.03 times the gas flow rate Q1 (| Q2-Q1 |> 0.0
In 3Q1), it was determined that a change occurred in the gas consumption state (1 gas appliance V was newly operated), and the absolute value of the flow rate difference was 0.03 times or less of the gas flow rate Q1. In this case (| Q2−Q1 | ≦ 0.03Q1), it is determined that the gas consumption state has not changed (there is no newly operated gas appliance). If it is determined that a change has occurred in the gas consumption state, the gas meter compares the gas flow rate Q3 measured most recently and the gas flow rate Q1 measured two times before (about 60 seconds before) at time T4. Flow difference (Q
3-Q1) is calculated, and this flow rate difference is registered as the individual flow rate of the newly operated gas appliance V. Subsequently, the gas meter determines whether the registered individual flow rate is equal to or higher than a predetermined flow rate (safe flow rate). If the individual flow rate is a safe flow rate, the gas meter determines that an excessive gas consumption state that does not occur in a normal gas use state is detected, and performs a series of warning operations. The gas meter is
At the time when the consumption state of the gas having a flow rate equal to or less than the predetermined flow rate is detected (time T5), it is determined that all the gas appliances have stopped.

[0006]

By the way, if the convenience of consumers using gas is taken into consideration, it is necessary to increase the reliability of the judgment regarding the execution of the warning operation and to avoid the malfunction of the warning operation. However, with conventional gas meters,
For the following reasons, there is a problem that the reliability of the determination regarding the execution of the warning operation is not sufficient. That is, as shown in FIG. 6, for example, after the operation of the gas appliance V during the time T2 to T3, another gas appliance W
Operates, the gas meter reads the individual flow rate corresponding to the flow rate difference Q5-Q1 at the time T4 even though the two gas appliances (the gas appliance V and the gas appliance W) are operating. It is determined that one gas appliance is operating. Since the individual flow rate at this time is the sum of the individual flow rates of the two gas appliances, it is a relatively large flow rate. In such a case, the individual flow rate becomes equal to or higher than the safe flow rate, and there is a high possibility that the warning operation is erroneously executed even though the two gas appliances are operating normally.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a gas meter and a method for determining an abnormality related to gas supply, which can improve the reliability of determination regarding execution of a warning operation. It is in.

[0008]

The gas meter according to the present invention comprises:
Flow rate measuring means for measuring the flow rate of the fuel gas consumed by one or more gas combustion devices at predetermined time intervals; and the most recently measured flow rate of the fuel gas measured by the flow rate measuring means. A flow rate difference calculating means for calculating a flow rate difference between the target flow rate and a comparative flow rate measured earlier, and a fuel gas by comparing an absolute value of the flow rate difference calculated by the flow rate difference calculating means with a reference flow rate; The flow rate difference determining means for determining whether or not the consumption state of the fuel gas has changed, and the result of determination by the flow rate difference determining means has been monitored, and a change has occurred from the determination that the fuel gas consumption state has not changed. The first to move to the judgment
After detecting the judgment transition state of the above, when detecting a second judgment transition state that shifts from the judgment that the fuel gas consumption state has changed to the judgment that no change has occurred, 1 or First operation determining means for determining that the operation state of one of the two or more gas-fired appliances has changed, and operating state of one gas-fired apparatus having changed by the first operation determination means When it is determined that the gas combustion device has operated in the process of changing the flow difference leading to this determination and the flow difference has changed in the positive region, it is determined that one gas combustion device has been operated. A second operation judging means for judging that one gas combustion device has stopped when the difference has changed in the negative region;
When the operation of one gas combustion device is determined by the operation determination means, the flow rate of the fuel gas corresponding to the most recently detected determination transition state and the fuel gas flow rate corresponding to the previously detected determination transition state are determined. Individual flow rate calculating means for calculating an individual flow rate of one gas combustion device operating as a difference from the flow rate of the fuel gas; and determining whether or not the individual flow rate calculated by the individual flow rate calculating means is greater than or equal to a safe flow rate. And a shutoff means for shutting off the supply of fuel gas to one or more gas combustion devices when the individual flow rate is judged to be equal to or higher than the safe flowrate by the safety judgment means. It is.

In the gas meter according to the present invention, the flow rate measuring means measures the instantaneous flow rate of the fuel gas consumed by one or two or more gas combustion devices at predetermined time intervals, and the flow rate difference calculating means measures the fuel gas. By calculating the flow difference between the most recently measured target flow and the comparison flow measured earlier than this, the flow difference determining means compares the absolute value of the flow difference with the reference flow. It is determined whether or not the fuel gas consumption state has changed. The result of the judgment by the flow rate difference judging means is monitored by the first operation judging means, and the first judgment is made to shift from the judgment that the fuel gas consumption state has not changed to the judgment that the change has occurred. After the transition state is detected,
When a second determination transition state is detected, in which the determination is made that a change has occurred in the fuel gas consumption state and a determination has been made that no change has occurred, one or more gas combustion devices It is determined that the operating state of the first gas combustion device has changed. When it is determined that the operating state of the first gas-fired device has changed, the second operation determining means determines that the flow rate difference has changed within a positive region in the process of changing the flow rate difference leading to this determination. Is determined to have operated one gas-fired device, while if the flow rate difference has changed in the negative region, it is determined that one gas-fired device has stopped. When the operation of the first gas combustion device is determined, the flow rate of the fuel gas corresponding to the most recently detected second determination transition state and the other second detected previously are determined by the individual flow rate calculating means. The individual flow rate of one gas combustion device operating as a difference from the flow rate of the fuel gas corresponding to the transition state is calculated, and the safety determination means determines whether the individual flow rate is equal to or greater than the safe flow rate. . When it is determined that the individual flow rate is equal to or higher than the safe flow rate, the supply of the fuel gas to one or more gas combustion devices is shut off by the shutoff means.

In the gas meter according to the present invention, the flow difference determining means determines that the fuel gas consumption state has changed when the absolute value of the flow difference calculated by the flow difference calculating means is equal to or greater than the reference flow rate. On the other hand, when the absolute value of the flow rate difference is smaller than the reference flow rate, it may be determined that the fuel gas consumption state has not changed.

In the gas meter according to the present invention, the reference flow rate may correspond to a predetermined multiple of the comparison flow rate.

In the gas meter according to the present invention, the flow rate difference calculating means performs a predetermined calculation process using the target flow rate, and then calculates a flow difference between the target flow rate after the calculation process and the comparison flow rate. You may do so.

In the gas meter according to the present invention, the flow difference calculating means may perform a predetermined calculation process using the calculated flow difference.

Further, in the gas meter according to the present invention, after the first operation judging means detects the second judgment shift state, the first operation judging means judges a predetermined number of times that the fuel gas consumption state has not changed. When the detection is continuously performed, it is determined that the operating state of one gas combustion device has changed, and the individual flow rate calculating means causes a change in the fuel gas consumption state by the flow rate difference determining means. The individual flow rate may be calculated using the average value of the flow rate of the fuel gas measured at each determination timing when it is determined that there is no flow rate.

Further, in the gas meter according to the present invention, the first operation determining means determines that the detection timing of the most recently detected second determination transition state is the other second determination transition state detected earlier than this. If it is within a predetermined time from the detection timing of the state, the recognition regarding the most recently detected second determination transition state may be deleted.

The abnormality determination method according to the present invention for gas supply comprises:
A first step of measuring the flow rate of the fuel gas consumed by the one or more gas-fired devices at predetermined time intervals, and the most recently measured target flow rate of the flow rate of the fuel gas and A second step of calculating a flow rate difference from the measured comparison flow rate, and a third step of comparing the absolute value of the flow rate difference with the reference flow rate to determine whether or not a change has occurred in the fuel gas various cost states; After detecting a first determination transition state in which a transition is made from a determination that a change has not occurred in the fuel gas consumption state to a determination that a change has occurred, it is assumed that a change has occurred in the fuel gas consumption state. When detecting the second determination transition state in which the determination is made that the change has not occurred, the operation state of one of the one or more gas combustion apparatuses has changed. A fourth step of determining as, 1
When it is determined that the operation state of the gas-fired device has changed, when the flow-rate difference changes within a positive range in the process of changing the flow-rate difference leading to this determination, one gas-fired device operates. A fifth step of determining that one gas-fired device has stopped if the flow rate difference has changed in the negative region, and determining the operation of one gas-fired device. When this is done, it operates as the difference between the flow rate of the fuel gas corresponding to the most recently detected second determination transition state and the flow rate of the fuel gas corresponding to the other second determination transition state detected earlier than this. A sixth step of calculating the individual flow rate of the one gas-fired device, a seventh step of determining whether the individual flow rate is equal to or higher than the safe flow rate, and determining that the individual flow rate is equal to or higher than the safe flow rate. Sometimes 1 or 2 or less In which the it was to include an eighth step of cutting off the supply of fuel gas to the gas burning appliance.

In the method for judging abnormality of gas supply according to the present invention, in the first step, the flow rate of fuel gas consumed by one or more gas combustion devices is measured at predetermined time intervals, and the second step is performed. In the step, a flow difference between the most recently measured target flow of the fuel gas flow and the comparative flow measured earlier than this is calculated,
In the third step, it is determined whether or not the fuel gas consumption state has changed by comparing the absolute value of the flow rate difference with the reference flow rate. Subsequently, in a fourth step, after detecting a first determination transition state in which the determination is made that a change has not occurred in the fuel gas consumption state, the first determination transition state is detected. When a second determination transition state is detected, in which a transition is made from a determination that a change has occurred in the consumption state of the gas combustion apparatus to a determination that no change has occurred, one or more of the one or more gas-fired appliances is detected. It is determined that the operating state of the gas combustion device has changed. Subsequently, in the fifth step, when it is determined that the operating state of one gas-fired device has changed, in the process of changing the flow difference leading to this determination, the flow difference changes within a positive region. If there is, it is determined that one gas combustion device has been operated, while if the flow rate difference has changed in the negative region, it is determined that one gas combustion device has stopped. Subsequently, in the sixth step, when the operation of one gas combustion device is determined, the flow rate of the fuel gas corresponding to the most recently detected second determination transition state and the flow rate of the fuel gas detected earlier than this are determined. The individual flow rate of one gas combustion device operating as a difference from the flow rate of the fuel gas corresponding to the other second determination transition state is calculated, and in the seventh step, the individual flow rate is equal to or greater than the safe flow rate. Is determined. Finally, in the eighth step, when it is determined that the individual flow rate is equal to or higher than the safe flow rate, the supply of the fuel gas to one or more gas combustion devices is cut off.

In the method for determining an abnormality related to gas supply according to the present invention, in the third step, when the absolute value of the flow rate difference is equal to or more than the reference flow rate, it is determined that the fuel gas consumption state has changed, On the other hand, when the absolute value of the flow rate difference is smaller than the reference flow rate, it may be determined that the fuel gas consumption state has not changed.

Further, in the abnormality determination method according to the present invention, the reference flow rate may be set so as to correspond to a predetermined multiple of the comparison flow rate.

Further, in the method for determining an abnormality related to gas supply according to the present invention, in the second step, after performing a predetermined calculation process using the target flow rate, a flow rate difference between the target flow rate after the calculation process and the comparison flow rate is obtained. May be calculated.

In the method for determining an abnormality related to gas supply according to the present invention, a tenth step of performing a predetermined calculation process using the calculated flow rate difference between the second step and the third step. May be included.

Further, in the abnormality determination method according to the present invention, in the fourth step, after detecting the second determination transition state, it is determined that no change has occurred in the fuel gas consumption state. It is determined that the operating state of one gas combustion device has changed when the detection is continuously performed for a predetermined number of times. In the sixth step, no change occurs in the fuel gas consumption state in the third step. The individual flow rate may be calculated using an average value of the flow rate of the fuel gas obtained at each determination timing.

In the method for judging abnormality of gas supply according to the present invention, in the fourth step, the detection timing of the most recently detected second judgment transition state is determined by the other second detection state detected earlier than this. If it is within a predetermined time from the detection timing of the judgment transition state, the recognition regarding the most recently detected second judgment transition state may be deleted.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a main part of a gas meter 10 according to an embodiment of the present invention. In addition,
“Abnormality determination method related to gas supply” according to the present embodiment
Is embodied by the gas meter 10, and will be described together below.

The gas meter 10 has a measuring section 11 for measuring the flow rate of the gas G flowing in the pipe inside the housing,
CPU (Ce) for controlling the operation of the entire gas meter 10
ntral Proccessing Unit; 12,
RAM (Random Access Memo) for storing various information
ry) 13, a clock 14 for measuring time, and C
Lithium battery 1 for supplying power to PU 12 and the like
5 and a shutoff valve 16 for switching the supply state of the gas G to the downstream side of the gas meter 10. In addition, a display unit 17 for displaying various information related to the gas meter 10 is provided on the outer surface of the housing.
Although not shown, it is assumed that one or more gas appliances (for example, a gas range, a gas water heater, a gas heater, etc.) are installed in the gas meter via a pipe. Here, the measuring unit 11 corresponds to a specific example of “flow rate measuring unit” in the present invention, and the shutoff valve 16 corresponds to a specific example of “cutoff unit” in the present invention.

The measuring section 11 is composed of, for example, a fluidic element or a thermal type flow sensor, and outputs a flow signal to the CPU 12 in accordance with the flow rate of the gas G flowing in the pipe. I have. By using the measuring unit 11 having such a configuration, it is possible to measure the instantaneous flow rate QS of the gas G, unlike the case of a membrane type flow meter or the like.

The CPU 12 mainly executes the clock 1
The flow signal output from the metering unit 11 is fetched at predetermined time intervals (for example, one second) based on the clock signal output from the counter 4, and the instantaneous flow QS of the gas G is calculated based on the flow signal. It has become. Also, CP
The U12 calculates the integrated flow rate QK of the gas G by integrating the instantaneous flow rate QS at predetermined time intervals (for example, one hour). The CPU 12 outputs the acquired series of flow rate data (QS, QK) to the display unit 17 and stores it in the RAM 13 as needed.

The CPU 12 has the following security function for the purpose of ensuring the safety of the consumer accompanying the use of the gas G. That is, the CPU 12
For example, first, after calculating the instantaneous flow rate QS of the gas G, the past 10 including the most recently calculated instantaneous flow rate QS
The average flow rate QSR is calculated as the average value of the instantaneous flow rates of the batches (moving average calculation processing). This moving average calculation process is performed, for example, after the CPU 12 starts calculating the instantaneous flow rate QS.
The process is started from the time when zero flow data (ten instantaneous flow QS) is obtained. Of course, this moving average calculation processing is repeatedly performed at each calculation timing of the instantaneous flow rate QS.

Subsequently, the CPU 12 calculates the average flow rate QSR (target flow rate) calculated most recently and the average flow rate QSR (comparison flow rate) calculated earlier (for example, 10 seconds before).
Is calculated. Here, FIG.
3 shows an example of the change (A) of the average flow rate QSR and the change (B) of the flow rate difference ΔQS, and explains the correlation between the two. In FIG. 2, the “horizontal axis” represents time T
(Seconds), and the “ordinate” indicates the average flow rate QSR or the flow rate difference ΔQS (L / h). When one gas appliance X operates / stops in a state where none of the gas appliances is operating, the average flow rate QSR increases in accordance with the operation of the gas appliance X and becomes substantially constant. Decreases as X stops. At this time, the flow rate difference ΔQS increases in accordance with the increase of the average flow rate QSR, and then increases.
It decreases when R becomes constant. When the operating gas appliance X stops, the flow rate difference ΔQS becomes the average flow rate Q
It decreases and then increases according to the decrease in SR. Where C
The PU 12 corresponds to a specific example of “flow rate difference calculating unit” in the present invention.

Subsequently, the CPU 12 performs a predetermined averaging operation using, for example, the calculated flow rate difference ΔQS. This averaging operation is performed using, for example, the following operation expression.

ΔQS = １ ／ ΔQS1 + 3 / 4ΔQS2

In the above equation, “ΔQS” is the flow rate difference after the averaging operation, “ΔQS1” is the most recently calculated flow rate difference, and “ΔQS2” is one time before (for example, one second before) “ΔQS”. The parentheses indicate the flow rate differences after the averaging operation.

Subsequently, the CPU 12 performs a predetermined truncation calculation process using the flow rate difference ΔQS after the averaging calculation process, for example. In this truncation calculation process, for example, “1 digit” of the flow rate difference ΔQS is truncated. Specifically, for example, when the flow rate difference ΔQS before the averaging calculation processing is “96 L / h”, this is set to “90 L / h”.
And However, the “digit” to which the truncation operation processing is applied is not necessarily limited to “1 digit”, and may be applied to a digit other than “1 digit” (eg, “10 digit”), or You may make it apply to several digits (for example, "1 digit" and "10 digit"). Of course, the above-described averaging operation and truncation operation are performed by the flow rate difference ΔQ
It is repeatedly performed at each calculation timing of S.

Subsequently, the CPU 12 calculates the absolute value (| ΔQS |) of the flow rate difference ΔQS after the truncation calculation processing as the reference flow rate Q
By comparing with SK, it is determined whether or not the gas G consumption state has changed. Specifically, the CPU 12
For example, it is determined whether or not the absolute value (| ΔQS |) of the flow rate difference ΔQS after the truncation calculation processing is equal to or larger than the reference flow rate QSK. The reference flow rate ΔQSK serves as a detection reference for detecting a change in the consumption state of the gas G, and is set in advance by, for example, a gas company and stored in the RAM 13. As the reference flow rate ΔQSK, for example,
A predetermined flow rate (for example, 100 L / h) may be fixed and registered, or a flow rate that is a predetermined multiple (for example, 0.03 times) of the average flow rate QSR (comparison flow rate) at each calculation timing of the flow rate difference ΔQS. May be calculated.
At this time, when the absolute value of the flow rate difference ΔQS is equal to or larger than the reference flow rate QSK (| ΔQS | ≧ QSK), the CPU 12 determines that the gas G consumption state has changed (the flow rate has changed), On the other hand, when the absolute value of the flow rate difference ΔQS is smaller than the reference flow rate (| ΔQS | <QSK), it is determined that the gas G consumption state has not changed (the flow rate does not change). Here, the CPU 12 corresponds to a specific example of “flow rate difference determination means” and “consumption state determination” in the present invention.

Here, referring again to FIG. 2, the flow rate difference ΔQ
The correlation between the change in S and the change in the consumption state of the gas G (change in the operation state of the gas appliance) will be described. As shown in FIG. 2, the “absolute value of flow rate difference ΔQS (| ΔQS |)
Is greater than or equal to the reference flow rate QSK? ”For each region in the change pattern of the flow rate difference ΔQS,
As described below, the CPU 12 determines a change in the gas G consumption state (“change in flow rate” or “no change in flow rate”). That is, in the change pattern of the flow rate difference ΔQS, the flow rate difference ΔQS is equal to or more than + QSR (ΔQS ≧ + QS
R) and the flow rate difference ΔQS is −QSR or less (Δ
In the region R2 of (QS ≦ −QSR), the absolute value of the flow rate difference ΔQS is equal to or larger than the reference flow rate QSK (| ΔQS | ≧ QSK), so that these regions R1 and R2 are determined to have “flow rate change”. On the other hand, the flow rate difference ΔQS is larger than −QSR and smaller than + QSR (−QSR <ΔQS
<+ QSR), the absolute value of the flow rate difference ΔQS is smaller than the reference flow rate QSK (| ΔQS | <QS
K), the region R3 is determined to be “no change in flow rate”. A point M1 in the figure corresponds to a state where the determination has shifted from “no flow rate change” to “flow rate change”, and a point M2 corresponds to the last “flow rate change” determination state after the point M1. , Point M3 corresponds to a state in which the determination content has shifted from “with flow rate change” to “without flow rate change”. The flow rate difference ΔQS changes within a positive region between the points M1 and M2, and the change in the flow rate difference ΔQS at this time corresponds to “operation” of the gas appliance. In addition, points M4 and M
5, M6 respectively correspond to the above points M1, M2, M3. The flow rate difference ΔQS changes in a negative region between the points M4 and M5, and the change in the flow rate difference ΔQS at this time corresponds to “stop” of the gas appliance. By monitoring the determination regarding the change in the consumption state of the gas G (“change in flow rate” or “no change in flow rate”),
It is possible to determine the operation state (operation, stop) of the gas appliance.

Subsequently, the CPU 12 monitors the determination result ("flow rate change" or "no flow rate change") regarding the change in the gas G consumption state, and changes the content from "no flow rate change" to "flow rate change". Is detected, the “first judgment transition state” to which the transition is made. Then, after detecting the “first determination transition state”, the CPU 12 continuously monitors the determination result regarding the change in the gas G consumption state, and changes the determination content from “with flow rate change” to “without flow rate change”. Transition "second judgment transition state"
Is detected. For example, between the “first determination transition state” and the “second determination transition state”, for example, the determination of “flow rate change” is continuously detected. When detecting the “second judgment transition state” after detecting the “first judgment transition state”, the CPU
12 judges that the operating state of one gas appliance has changed. Here, the CPU 12 corresponds to a specific example of “first operation determination unit” in the present invention.

Subsequently, for example, the CPU 12 checks whether or not another "second judgment transition state" has been detected before the most recently detected "second judgment transition state". At this time, when another “second judgment transition state” is detected, for example, the “second judgment transition state” most recently detected from the detection timing of the other “second judgment transition state” If the time until the detection timing (detection interval TH) is shorter than a predetermined time (detection allowable time TY; for example, 5 seconds) (TH ≦ TY), the CP
U12 is the most recently detected “second judgment transition state”
Is determined to be due to a factor other than the use of the gas G (for example, pulsation of the gas G), and the recognition regarding the “second determination transition state” at this time is deleted. When the detection interval TH is longer than the permissible detection time TY (TH> TY), the CPU 12 determines that the most recently detected “second determination transition state” has occurred in response to the operation or stoppage of the gas appliance. Judge. Such a determination regarding the detection interval TH in the “second determination transition state” is performed at each detection timing of the “second determination transition state”.

Subsequently, when detecting the "second judgment transition state" which is not to be deleted, the CPU 12 determines the flow rate difference ΔQS between the "first judgment transition state" and the "second judgment transition state". In the changing process, it is determined whether the flow rate difference ΔQS has changed in the positive region or has changed in the negative region. At this time, the CPU 12 determines the flow rate difference ΔQS
Is changed in the positive region, it is determined that one gas appliance X is newly operated. On the other hand, when the flow rate difference ΔQS is changed in the negative region, one gas appliance X is changed. It is determined that X has stopped. Here, the CPU 12 corresponds to a specific example of “second operation determining means” in the present invention.

Subsequently, the CPU 12 registers the average flow rate QSR of the gas G corresponding to the “second determination transition state” as the flow rate increase amount, that is, the individual flow rate QBX of the gas appliance X, and stores it in the RAM 13.

Subsequently, the CPU 12 determines whether or not the individual flow rate QBX is equal to or greater than the safe flow rate QZ. This “safe flow rate QZ” is, for example, an increase in the instantaneous flow rate QS of the gas G when two arbitrary gas appliances having a large gas consumption amount are simultaneously operated among a plurality of gas appliances installed in the consumer's house. The flow rate is set by a gas company or the like so as to be in a range larger than the amount, and is stored in the RAM 13 in advance. When the individual flow rate QBX is equal to or greater than the safe flow rate QZ (QBX ≧ QZ), the CPU 12
Then, it is determined that an excessive gas G consumption state that does not occur in the use state is detected, and a warning operation is performed. At this time, the CPU 12 performs, for example, the shutoff valve 1 as a warning operation.
The supply of the gas G to the gas appliance is interrupted by outputting the valve drive signal S to the valve 6 and driving the shutoff valve 16 (individual flow rate over interrupt). If the individual flow rate QBX is smaller than the safe flow rate QZ (QBX <QZ), C
The PU 12 determines that the normal gas G usage state has been detected. Here, the CPU 12 corresponds to a specific example of “safety determination means” in the present invention.

Although the case where one gas appliance X is operated in a state where none of the gas appliances is operating has been described above, other gas appliances are operated in a state where one gas appliance X is operated in advance. In a case where the appliance Y operates, the CPU 12 determines the average flow rate QSR of the gas G corresponding to the “second determination transition state” detected according to the operation of the gas appliance Y and the operation of the gas appliance X. The individual flow rate QBY of the gas appliance Y as a difference from the average flow rate QSR of the gas G corresponding to the “second determination transition state” detected at the time (ie, the individual flow rate QBX registered when the gas appliance X is operating).
(= QSR-QBY) is calculated and registered. of course,
Similarly, when three or more gas appliances operate sequentially, the operation of each gas appliance is recognized at any time, and their individual flow rates are sequentially calculated. Here, the CPU 12 corresponds to a specific example of “individual flow rate calculation means” in the present invention.

The above-mentioned "measurement timing of instantaneous flow rate QS (for example, one second)" and "the number of instantaneous flow rates QS used for calculating average flow rate QSR (moving average width; for example, 10
), "Selection timing of instantaneous flow rate QS (comparison flow rate) used when calculating flow rate difference ΔQS (for example, instantaneous flow rate QS 10 seconds before)", and "digit to be truncated in truncation calculation processing (for example, 1 digit)""And" Permissible detection time TY "
(For example, 5 seconds) "can be freely changed.

The CPU 12 also has various shut-off mechanisms other than the individual flow rate over shut-off mechanism. Specifically, for example, for each gas G consumption (for example, individual flow rate or total flow rate), the time (continuous time) in which the gas G can be continuously consumed is registered in advance, and the gas G consumption time is registered in advance. One that shuts off the supply of gas G when the continuous time is reached (duration over cut off), and shuts off the supply of gas G when the total flow rate of gas G reaches a preset flow rate (safe maximum flow rate) What to do (total flow rate over cutoff)
And so on.

Subsequently, referring to FIG.
A configuration example of 0 will be described. The shut-off valve 16 is connected to the CPU 1
It is driven in accordance with the valve drive signal S output from 2 to shut off the supply of gas G to the gas appliance.

The display section 17 is composed of, for example, a display panel or the like, and is configured to display information such as flow rate data (QS, QK) of the gas G and the driving status of the shut-off valve 16. A consumer or a gas company can grasp the usage status of the gas G by visually checking the display unit 17.

Next, the operation of the gas meter 10 according to the present embodiment will be described with reference to FIGS. Here, FIG. 3 and FIG. 4 are flowcharts for explaining the operation of the gas meter 10. In the following, for example, in a state where one gas appliance X is operating in advance (the individual flow rate QBX of the gas appliance X has been registered), the other gas appliances Y are mainly described.
The operation of the CPU 12 relating to the security function (individual flow rate over shutoff mechanism) when the system operates will be described.

In the gas meter 10, first, the measuring section 1
1 is operated, and the instantaneous flow rate QS of the gas G is calculated at predetermined time intervals (for example, one second) (FIG. 3: step S10).
1). Subsequently, for example, the most recently calculated instantaneous flow rate Q
The average flow rate QSR is calculated as an average value of the instantaneous flow rates of the past 10 times including S (moving average calculation processing, FIG. 3; step S102). Subsequently, a flow difference ΔQS between the most recently calculated average flow rate QSR (target flow rate) and the average flow rate QSR (comparative flow rate) calculated earlier (for example, 10 seconds before) is calculated (FIG. 3; step S103). ).

Subsequently, a predetermined averaging calculation process is performed using the calculated flow rate difference ΔQS (FIG. 3, step S10).
4). As this averaging calculation processing, for example, the flow rate difference after the averaging calculation processing is “ΔQS”, and the flow rate difference calculated most recently is “ΔQS1”, which is averaged one time before (eg, one second before) “ΔQS”. The flow rate difference that has been subjected to the
When “2” is set, “ΔQS = 1 / 4ΔQS1 + 3 / 4Δ”
QS2 ”. Subsequently, a predetermined truncation calculation process is performed using the flow rate difference ΔQS after the averaging calculation (FIG. 3; step S105). In this truncation calculation process, for example, “1 digit” of the flow rate difference ΔQS is truncated.

Subsequently, the flow rate difference ΔQ after the truncation calculation processing is performed.
It is determined whether the absolute value of S (| ΔQS |) is equal to or greater than the reference flow rate QSK (FIG. 3; step S106). At this time, when the absolute value of the flow rate difference ΔQS is equal to or larger than the reference flow rate QSK (| ΔQSR | ≧ QSK, FIG. 3; step S10).
6Y), it is determined that a change has occurred in the gas G consumption state (flow rate change has occurred), and the determination content changes from “no flow rate change” to “flow rate change has occurred” “state after first determination” Is detected (FIG. 3; step S107). Then, CPU1
No. 2 detects a “state after the second judgment” in which the judgment content changes from “with flow rate change” to “without flow rate change” (FIG. 3; step S108). If the absolute value of the flow rate difference ΔQS is smaller than the reference flow rate QSK (| ΔQS | <QSK, FIG. 3; step S106N), it is determined that the gas G consumption state has not changed, and the instantaneous flow rate QS (Step S101).

Subsequently, it is confirmed whether another "state after the second judgment" has not been detected before the most recently detected "state after the second judgment" (FIG. 4, step S109). At this time, another "state after the second determination"
(FIG. 4; step S109Y), the time (detection time) from the detection timing of the other “state after the second determination” to the detection timing of the most recently detected “state after the second determination” It is determined whether or not the interval TH) is equal to or shorter than a predetermined time (detection allowable time TY; for example, 5 seconds) (FIG. 4; step S110). If the detection interval TH is shorter than the allowable detection time TH (TH ≦ TY, FIG. 4; step S110Y), the most recently detected “state after the second determination” is a factor other than the use of the gas G (for example, gas G pulsation, etc.), and the recognition regarding the “state after the second determination” at this time is deleted. If the detection interval TH is longer than the permissible detection time TY (TH> TY, FIG. 4; step S110N), the detected “state after the second judgment” occurs in response to the operation or stoppage of the gas appliance. Is determined to be.

Subsequently, the "first judgment shift state" to the "second judgment shift state"
It is determined whether or not the flow rate difference ΔQS has changed within a positive region in the process of changing the flow rate difference ΔQS in the “determination transition state” (FIG. 4; step S111). Note that, at the time of the above-described detection confirmation of the other “second determination transition state” (step S109), the other “second determination transition state” is performed before the most recently detected “second determination transition state”. Is not detected (FIG. 4; step S10).
9N), the above-described “determination regarding the detection interval TH (step S110)” is omitted, and the process proceeds to “determination regarding confirmation of a change region of the flow rate difference ΔQS (step S111)”. At this time, if the flow rate difference ΔQS has changed within the positive region (FIG. 4; step S111Y), it is determined that one gas appliance Y has newly operated, and The average flow rate QSR corresponding to the detected “second determination transition state” and the average flow rate QSR corresponding to the “second determination transition state” detected according to the operation of the gas appliance X
(That is, the individual flow rate QB of the gas appliance Y as a difference from the registered individual flow rate QBX when the gas appliance X is in operation).
Y (= QSR-QBX) is calculated (FIG. 4: step S
112). This individual flow rate QBY is registered as an increase in the consumption amount of the new gas G, and is stored in the RAM 13.
When the flow rate difference ΔQS has not changed in the positive region (when the flow difference ΔQS has changed in the negative region,
In FIG. 4; step S111N), it is determined that the gas appliance X that has been operating in advance has stopped, and the registered individual flow rate QBX of the gas appliance X is deleted.

Subsequently, it is determined whether or not the calculated individual flow rate QBY is equal to or greater than the safe flow rate QZ (FIG. 4; step S113). At this time, the individual flow rate QBY is changed to the safe flow rate QZ.
If the above is the case (QBY ≧ QZ, FIG. 4; step S11)
3Y), it is determined that an excessive gas G consumption state that does not occur in a normal gas G use state is detected, and a valve drive signal S is output to the shutoff valve 16 (FIG. 4; step). S114). Thereby, the shutoff valve 16 is driven, and the supply of the gas G to the gas appliance is shut off. When the individual flow rate QBY is smaller than the safe flow rate QZ (QBY <Q
Z, FIG. 4; step S113N), it is determined that the normal use state of the gas G has been detected, and the process returns to the measurement of the instantaneous flow rate QS (FIG. 3; step S101).

As described above, in the gas meter 10 and the abnormality determination method according to the gas supply according to the present embodiment, the change in the consumption state of the gas G (“with flow rate change” or “without flow rate change”) is monitored. "First judgment transition state"
And when the “second judgment transition state” is sequentially detected,
It is determined that the operating state of the gas appliance has changed, and in particular, when the flow rate difference ΔQS changes within the positive region between the “first determination transition state” and the “second determination transition state”, 1 Is determined to be newly operated. In such a case, unlike the conventional case where the gas G consumption state by a plurality of gas appliances operated continuously is erroneously determined as the gas G consumption state by one gas appliance, Since the operation of the gas appliance is accurately recognized at any time, the individual flow rate of each gas appliance is accurately calculated, and the warning operation is properly executed. Therefore, it is possible to improve the reliability of the determination regarding the execution of the warning operation. Thereby, the convenience of the consumer using the gas G is improved.

Further, in the present embodiment, the time required for calculating the individual flow rate of the operated gas appliance can be reduced for the following reasons. That is, in the conventional gas meter (see FIG. 5), since the flow rate of the gas G is measured about every 30 seconds due to the structural limitation of the membrane flow meter, the gas flow rate increases with the operation of the gas appliance V. It takes about 60 seconds from time to time T4 to calculate the individual flow rate of the gas appliance V. On the other hand, in the present embodiment (see FIG. 2), the gas flow rate (average flow rate QSR) increases with the operation of the gas appliance X and then the individual flow rate QBX of the gas appliance X is calculated (point M3). ) Is 30 seconds or less.

In this embodiment, the average flow rate QSR is calculated by performing a moving average calculation process using the instantaneous flow rate QS (target flow rate) of the gas G, and then the flow rate difference ΔQS is calculated using the average flow rate QSR. Is calculated, the fluctuation of the average flow rate QSR due to the pulsation of the gas G or the like is suppressed. Therefore, the fluctuation of the flow rate difference ΔQS is suppressed, and the operating state of the gas appliance can be accurately determined. The above effects can be obtained similarly by performing the averaging calculation processing and the truncation calculation processing using the flow rate difference ΔQS.

Further, in the present embodiment, it is determined whether or not the detection interval TH is equal to or less than the allowable detection time TY at each detection timing of the “second judgment shift state”, and the detection interval TH is set to the allowable detection time TY. In the following case, the recognition regarding the “second judgment transition state” is deleted, so that even if the flow difference ΔQS fluctuates due to the pulsation of the gas G or the like, the flow difference ΔQS Fluctuations can be excluded from the target of execution determination of the warning operation.

In this embodiment, the moving average calculation processing is performed after measuring the instantaneous flow rate QS of the gas G. However, the present invention is not limited to this. For example, the moving average calculation processing is performed. Instead, the flow rate difference ΔQS may be calculated using the instantaneous flow rate QS as it is. However, if it is desired to suppress the fluctuation of the flow rate difference ΔQS caused by the pulsation of the gas G, it is preferable to perform the moving average calculation processing.

In this embodiment, after calculating the flow rate difference ΔQS, both the averaging calculation processing and the truncation calculation processing are performed using the flow rate difference ΔQS.
It is not necessarily limited to this. For example, only one of the averaging operation processing and the truncation operation processing may be performed, or none of the operation processing may be performed. However, if it is desired to suppress the fluctuation of the flow rate difference ΔQS caused by the pulsation of the gas G, it is preferable to perform both the averaging calculation processing and the truncation calculation processing. The execution order of the arithmetic processing is arbitrary,
The averaging operation may be performed after the truncation operation. Further, after calculating the flow rate difference ΔQS, the moving average calculation processing may be performed using the flow rate difference ΔQS.

Further, in the present embodiment, when the "second judgment transition state" is detected after the "first judgment transition state" is detected, the operating state of one gas appliance changes. However, the present invention is not necessarily limited to this. For example, after detecting the “second determination transition state”, the determination that there is no change in the consumption state of the gas G (no change in flow rate) is continuously performed a predetermined number of times (for example, two times). When it is detected, it may be determined that a change has occurred in the operating state of one gas appliance. Thereby, even if the flow rate difference ΔQS fluctuates due to the pulsation of the gas G or the like, the fluctuation of the flow rate difference ΔQS at this time can be excluded from the execution determination target of the warning operation, and
The operating state of the gas appliance can be determined more accurately. In the above case, the gas flow rate (average flow rate QSR) measured at each determination timing (determination timing of “no change in flow rate”) assuming that the gas G consumption state has not changed has been determined. Individual flow QB using average value
Y may be calculated. Alternatively, after calculating a plurality of individual flow rates QBY using the gas flow rate (average flow rate QSR), an average value of the plurality of individual flow rates QBY may be calculated.

In this embodiment, a round-up operation or a round-off operation may be performed instead of the round-down operation. In either case, for example, the “one digit” of the flow rate difference ΔQS is rounded up or rounded off. Specifically, in the round-up calculation processing, for example, when the flow rate difference ΔQS before the averaging calculation processing is “92 L / h”, this is set to “100 L / h”.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, in order to suppress the fluctuation of the flow rate difference ΔQS caused by the pulsation of the gas G or the like, the moving average calculation processing and the averaging calculation processing are performed in a series of determination processes related to the execution of the warning operation. And the truncation operation processing is performed, but the type of operation processing is not necessarily limited to these, and various operation processing other than the above may be performed.

[0063]

As described above, the gas meter according to any one of claims 1 to 7 or the abnormality determination method according to any one of claims 8 to 14 according to the gas supply. According to the above, based on the determination regarding the change in the fuel gas consumption state obtained by comparing and determining the absolute value of the flow rate difference and the reference flow rate, a change occurs from the determination that no change has occurred in the fuel gas consumption state. After detecting a transition state, a second decision is made to shift from a determination that a change has occurred in the fuel gas consumption state to a determination that no change has occurred. When the transition state is detected, it is determined that the operating state of the one gas combustion device has changed. In such a case, when a plurality of gas-fired devices operate, the operation of each gas-fired device is accurately recognized at any time, so the individual flow rate of each gas-fired device is accurately calculated, and the warning operation is properly performed. Be executed. Therefore, it is possible to improve the reliability of the determination regarding the execution of the warning operation.

In particular, according to the gas meter described in claim 4 or the abnormality determination method according to the gas supply described in claim 11,
After performing a predetermined calculation process using the target flow rate, the flow rate difference between the target flow rate after the calculation and the comparison flow rate is calculated, so that variation in the flow rate difference due to pulsation of the fuel gas or the like is suppressed, It is possible to accurately determine the operation state of the gas combustion device.

Further, according to the gas meter described in claim 5 or the abnormality determination method relating to gas supply described in claim 12,
Since the predetermined calculation process is performed using the calculated flow difference, variation in the flow difference due to pulsation of the fuel gas or the like is suppressed, and the operating state of the gas combustion device can be accurately determined.

According to the gas meter described in claim 6 or the abnormality determination method according to the gas supply described in claim 13,
After detecting the second determination transition state, when the determination that no change has occurred in the fuel gas consumption state is continuously detected for a predetermined number of times, the operating state of one gas combustion device changes. Therefore, even if the flow rate difference fluctuates due to the pulsation of the fuel gas or the like, the change in the flow rate difference at this time can be excluded from the execution determination target of the warning operation. The operating state of the combustion equipment can be more accurately determined.

Further, according to the gas meter described in claim 7 or the abnormality determination method according to gas supply described in claim 14,
If the detection timing of the most recently detected second determination transition state is within a predetermined time from the detection timing of another previously detected second determination transition state, the most recently detected second determination transition state is detected. Since the recognition relating to the determination transition state of No. 2 is deleted, the fluctuation of the flow rate difference caused by the pulsation of the fuel gas or the like can be excluded from the execution determination target of the warning operation.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining a correlation between an average flow rate and a flow rate difference.

FIG. 3 is a flowchart for explaining the operation of the gas meter.

FIG. 4 is a flowchart illustrating the operation subsequent to FIG. 3;

FIG. 5 is a diagram for explaining a determination procedure related to execution of a warning operation in a conventional gas meter.

FIG. 6 is a diagram for explaining a problem in a determination procedure related to execution of a warning operation of a conventional gas meter.

[Explanation of symbols]

10 gas meter, 11 measuring unit, 12 CPU, 13
... RAM, 14 ... clock, 15 ... lithium battery,
16 ... shut-off valve, 17 ... display, detection interval ... TH, TY ...
Allowable detection time, QBX, QBY: individual flow rate, QK: integrated flow rate, QS: instantaneous flow rate, QSK: reference flow rate, QSR: average flow rate, QZ: safe flow rate, ΔQS: flow rate difference.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsunori Komaki Tokyo Gas Co., Ltd. 1-5-20 Kaigan, Minato-ku, Tokyo (72) Inventor Takeshi Ken Tashiro 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas (72) Inventor: Issei Imao 70, Yanagicho, Yuki-ku, Kawasaki, Kanagawa Prefecture, Japan Inside the Toshiba Yanagicho Office (72) Inventor: Hiroto Uyama, 70, Yanagicho, Yukicho, Kawasaki, Kanagawa Prefecture, Japan ) Inventor Jiro Ishino 70 Yanagicho, Yuki-ku, Kawasaki-shi, Kanagawa Prefecture F-term in Toshiba Yanagicho Plant (reference) 2F030 CB01 CC13 CE02 CE04 CE21 CF05 CF11

Claims (14)

[Claims] 1. A flow rate measuring means for measuring a flow rate of a fuel gas consumed by one or more gas combustion devices at predetermined time intervals, and a flow rate of the fuel gas measured by the flow rate measuring means. A flow difference calculating means for calculating a flow difference between the most recently measured target flow rate and a comparative flow rate measured earlier than this, and an absolute value of the flow difference calculated by the flow difference calculating means is compared with a reference flow rate. The flow rate difference determining means for determining whether a change has occurred in the fuel gas consumption state, and monitoring the determination results by the flow rate difference determining means to determine that the fuel gas consumption state has not changed. After detecting the first determination transition state in which the determination is shifted to the determination that a change has occurred, no change has occurred from the determination that the change in the fuel gas consumption state has occurred. A first operation that determines that the operating state of one of the one or more gas-fired devices has changed when detecting a second determination-transition state that shifts to the determination of Determining means, when the first operation determining means determines that the operating state of the one gas-fired device has changed, in the process of changing the flow rate difference leading to this determination, the flow rate difference is within a positive region. If it has changed, it is determined that one gas-fired device has operated, while if the flow rate difference has changed in the negative region, it is determined that one gas-fired device has stopped. And a flow rate of the fuel gas corresponding to the most recently detected second determination transition state when the operation of the first gas combustion device is determined by the second operation determination means. Detected earlier than Individual flow rate calculating means for calculating the individual flow rate of one gas combustion device operating as a difference from the flow rate of the fuel gas corresponding to the second judgment transition state, and the individual flow rate calculated by the individual flow rate calculating means Determining whether or not the fuel flow rate is equal to or greater than a safe flow rate; and supplying the fuel gas to the one or more gas combustion devices when the safety determining means determines that the individual flow rate is equal to or greater than the safe flow rate. And a shutoff means for shutting off the gas. 2. The flow rate difference determining means determines that a change has occurred in the fuel gas consumption state when the absolute value of the flow rate difference calculated by the flow rate difference calculation means is equal to or greater than a reference flow rate. 2. The gas meter according to claim 1, wherein when the absolute value of the flow rate difference is smaller than the reference flow rate, it is determined that the fuel gas consumption state has not changed. 3. The gas meter according to claim 1, wherein the reference flow rate corresponds to a predetermined multiple of the comparison flow rate. 4. The method according to claim 1, wherein the flow rate difference calculating means calculates a flow rate difference between the target flow rate after the calculation processing and the comparison flow rate after performing a predetermined calculation process using the target flow rate. The gas meter according to any one of claims 1 to 3, characterized in that: 5. The gas meter according to claim 1, wherein the flow difference calculating means performs a predetermined calculation process using the calculated flow difference. 6. The first operation judging means, after detecting the second judgment transition state, continuously judges, for a predetermined number of times, that the fuel gas consumption state has not changed. When it is detected, it is determined that the operating state of one gas combustion device has changed, and the individual flow rate calculating means assumes that the fuel gas consumption state by the flow rate difference determining means has not changed. The gas meter according to any one of claims 1 to 4, wherein the individual flow rate is calculated using an average value of the flow rate of the fuel gas measured at each determination timing. 7. The first operation judging means sets the detection timing of the most recently detected second judgment transition state from the detection timing of another second judgment transition state detected earlier than this. The method according to any one of claims 1 to 6, wherein when the predetermined time has elapsed, the recognition of the most recently detected second determination transition state is deleted. Gas meter. 8. A first step of measuring the flow rate of fuel gas consumed by one or more gas-fired devices at predetermined time intervals; and determining the most recently measured target flow rate of the flow rate of fuel gas. A second step of calculating a flow rate difference from a comparative flow rate measured earlier than this, and a step of comparing the absolute value of the flow rate difference with a reference flow rate to determine whether a change has occurred in the fuel gas consumption state. Step 3, and a first judgment transition state where a transition is made from a judgment that the fuel gas consumption state has not changed to a judgment that a change has occurred to the fuel gas consumption state is detected, and then the fuel gas consumption state changes. When detecting a second judgment transition state in which the judgment is made that the change has occurred and the judgment that no change has occurred, when one of the one or more gas combustion appliances is detected, A fourth step of determining that the operating state has changed; and, when determining that the operating state of the gas-fired device has changed, in the process of changing the flow rate difference leading to this determination, the area where the flow rate difference is positive It is determined that one gas-fired device has been operated when it has changed within the range, while it has been determined that one gas-fired device has stopped when the flow rate difference has changed within the negative region. A fifth step of determining when the operation of the gas-fired device is determined, and determining the flow rate of the fuel gas corresponding to the most recently detected second determination transition state and the other second detection level detected earlier. A sixth step of calculating an individual flow rate of one gas-fired device operating as a difference from the flow rate of the fuel gas corresponding to the determination transition state; and a step of determining whether the individual flow rate is equal to or greater than the safe flow rate. 7 steps and before When it is determined that the individual flow rate is equal to or higher than the safe flow rate,
An eighth step of shutting off the supply of the fuel gas to the one or more gas-fired appliances. 9. In the third step, when the absolute value of the flow rate difference is equal to or greater than the reference flow rate, it is determined that a change has occurred in the fuel gas consumption state. 9. The method according to claim 8, wherein when the flow rate is smaller than the flow rate, it is determined that the fuel gas consumption state has not changed. 10. The abnormality determination method according to claim 8, wherein the reference flow rate is set so as to correspond to a predetermined multiple of the comparison flow rate. 11. In the second step, after performing a predetermined calculation process using the target flow rate, a flow difference between the target flow rate after the calculation process and the comparison flow rate is calculated. An abnormality determination method according to any one of claims 8 to 10. 12. The method according to claim 8, further comprising, between the second step and the third step, a tenth step of performing a predetermined calculation process using the calculated flow rate difference. Or claim 1
2. The abnormality determination method according to claim 1, wherein the abnormality is determined. 13. In the fourth step, after detecting the second judgment transition state, the judgment that the fuel gas consumption state has not changed is detected continuously for a predetermined number of times. Sometimes, it is determined that the operating state of the gas-fired device has changed, and in the sixth step, the measurement is performed at each determination timing in which it is determined that the fuel gas consumption state in the third step has not changed. The method according to any one of claims 8 to 12, wherein after calculating a plurality of individual flow rates using the obtained flow rate of the fuel gas, an average value of the plurality of individual flow rates is calculated. An abnormality determination method related to gas supply. 14. In the fourth step, the detection timing of the most recently detected second judgment transition state is:
If the detection timing of another second judgment transition state detected earlier than this is within a predetermined time, the recognition regarding the most recently detected second judgment transition state is deleted. An abnormality determination method according to any one of claims 8 to 13.