JP2001281089A - Gas meter and method for detecting gas leakage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas meter together with a gas leakage detecting method wherein a gas leakage in an early stage is detected while erroneous gas leakage detecting is prevented. SOLUTION: Within a learning period TG, consumption of gas G by a consumer is learned, and after during the learning period TG passed, a comparison flow-rate QH is so set as to be equal to a minimum flow-rate (QK1) among a reference flow-rate QK. If a consumption state of the gas G where an objective flow-rate QT is smaller than the comparison flow-rate QH is, detected for a specified period (tolerable continual time TK2; for example TK2=24 hours) when the learning period TG passed, supply of the gas G is cut off. Gas leakage is judged based on the consumption state G by a user, so reliability in detection of gas leakage is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas meter having a function of detecting leakage of gas flowing through a flow path and a method of detecting gas leakage.

[0002]

2. Description of the Related Art In recent years, in order to measure the consumption (gas flow rate) of household fuel gas (hereinafter, also simply referred to as "gas") accompanying consumption by consumers, a membrane flow meter or a fluidic flow meter has been used. Gas meters using such flow meters have been put to practical use. Recently, in addition to measuring a gas flow rate (eg, instantaneous flow rate, integrated flow rate), the flow rate of a gas flowing through a flow path (eg, instantaneous flow rate) is monitored. It is also known to have a function (security function) that determines that an abnormality has occurred and issues an alarm or shuts off the gas flow path. These security operations such as monitoring, judgment, and interruption are independently performed by a microcomputer mounted on the gas meter. According to this type of gas meter, it is possible to detect abnormalities such as gas leaks in various gas combustion devices (for example, a gas range) and pipes connected to the gas meter, and it is possible to detect safety of a customer accompanying the use of gas. Can be increased.

Here, referring to FIGS. 15 and 16,
A gas leak detection method in a gas meter using a conventional membrane flow meter will be described. FIG. 15 illustrates an example of an operation timing regarding a series of security operations of the gas meter when it is determined that there is no gas leak (without issuing an alarm),
FIG. 16 shows a case where it is determined that there is a gas leak (warning issuance).
5 shows an example of an operation timing relating to a series of security operations of the gas meter in FIG. In both figures, (A) increase / decrease of gas flow rate, (B) output of flow rate pulse P, (C) start / end of time measurement (clock count) (START / END), (D) alarm Represents the output of the signal. The horizontal direction in both figures (the direction of the arrow from left to right in the figures) indicates the passage of time.

As is well known, the membrane type flow meter is configured to output a flow rate pulse P in accordance with rotation of the membrane chamber due to a flow of gas. , The gas flow rate can be measured. The output interval of the flow pulse P depends on the magnitude of the gas flow. In a gas meter configured using such a membrane type flow meter, for example, detection of gas leakage is performed as follows. That is, the microcomputer mounted on the gas meter uses the clock signal output from the clock for performing the time measurement to start the flow rate pulse P at certain time intervals (for example, every one hour) starting at a certain time. Monitor for the presence of output. At this time, in a state where the flow pulse P is not detected for at least one hour or more, time measurement is performed based on the clock signal from the time when one flow pulse P is detected (clock count). For example, when 720 hours = 30 days (permissible continuation time T _K1 ) are detected continuously for at least one time unit including at least one flow pulse P per hour, it is determined that there is a gas leak and an alarm signal is output. Then, a series of warning operations for shutting off the gas supply by driving the shutoff valve are performed (continuous time recognition shutoff).

For example, in the example shown in FIG. 15, gas flow rates Q _A , Q
_A flow pulse P is output with the occurrence of _B , and a clock count is started in response to the detection of the flow pulse P (clock count START). Then, the clock count ends in a state where the flow pulse P is not detected for one hour or more (clock count EN).
D). At this time, the elapsed time (clock count time T _C1 ) from the clock count START to the clock count END is equal to the continuation allowable time T _K1 (for example, T _K1 = 720).
If the time is smaller than (time) (T _C1 <T _K1 ), it is not determined that a gas leak has occurred, and no alarm signal is output.

[0006] In contrast, for example, in the example shown in FIG. 16, in addition to the flow rate pulse P with the evolution of gas flow rate Q _A by the use of gas-fired equipment is being output, pilot flame operation etc. of the gas burning appliances flow pulse P with the occurrence of minute gas flow rate Q _C by or gas leak or the like is output. At this time, when the clock count time T _C1 becomes equal to or longer than the continuation allowable time T _K1 (T _C1 ≧ T _K1 ), it is determined that gas leakage has occurred, and an alarm signal is output.

As described above, conventionally, the occurrence of gas leakage is determined by regarding the continuous detection of the flow rate pulse P as the continuous occurrence of a gas flow rate.

[0008]

However, the conventional gas leak detection method cannot cope with gas combustion equipment that operates intermittently at constant or irregular intervals of less than a unit time. That is, as shown in FIG. 17, the unit time gas equipment in the following intervals (1 hour in this case) when operated intermittently, the flow rate pulse P is output along with the evolution of gas flow Q _A. Therefore, as a result, the clock count time T based on the output of the flow pulse P
_C1 is equal to or longer than the continuation allowable time T _K1 (T _C1 ≧ T _K1 ), and the occurrence of gas leakage is determined in the same manner as in the case of FIG.

As described above, according to the conventional gas meter and the gas leak detection method, even though the operation of the intermittently operating gas combustion equipment is normal, the gas leak is erroneously determined, and a warning operation (for example, a gas operation) is performed. In some cases, supply was cut off, which was inconvenient for consumers. In addition, as described above, it takes a long time (permissible continuation time) of, for example, 720 hours = 30 days before it is determined that a gas leak has occurred, and thus it is difficult to perform gas leak detection early. .

The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas meter and a gas leak detection method which enable early gas leak detection and prevent erroneous gas leak detection. It is in.

[0011]

The gas meter according to the present invention comprises:
The learning flow rate of the fuel gas consumed by one or more gas-burning appliances during the first period is measured every unit time, and after the first period, the learning flow rate of the fuel gas is measured.
Or a flow rate measuring means for measuring a target flow rate of the fuel gas consumed by two or more gas combustion devices per unit time, and setting a comparative flow rate based on a learning flow rate when the first period has elapsed, and A flow rate determining means for determining whether or not the target flow rate is smaller than the comparative flow rate after the elapse of the period;
When the state in which the target flow rate is smaller than the comparison flow rate has continued over the second period after the elapse of the period,
The gas flow path is provided with a leak determination means for determining that gas has leaked.

According to the gas leak detection method of the present invention, a learning flow rate of fuel gas consumed by one or more gas combustion devices within a first period is measured for each unit time, and when the first period elapses. Setting the comparison flow rate based on the learning flow rate, measuring the target flow rate of the fuel gas consumed by one or more gas-burning devices at each unit time after the elapse of the first period, and comparing the target flow rates. It is determined whether or not the flow rate is smaller than the flow rate, and when the state in which the target flow rate is smaller than the comparison flow rate continues over the second period,
It is determined that a gas leak has occurred in the gas flow path.

[0013] In the gas meter or the gas leak detection method of the present invention, the learning flow rate of the fuel gas consumed by one or more gas-burning devices during the first period is measured, and when the first period elapses. In, the comparison flow rate is set based on the learning flow rate, and the target flow rate of the fuel gas consumed by one or more gas combustion devices after the first period has elapsed is measured. Then, after a lapse of the first period, when a state in which the target flow rate is smaller than the comparison flow rate continues over the second period, it is determined that gas has leaked in the gas flow path. You.

In the gas meter or the gas leak detection method according to the present invention, the comparison flow rate may be set to be equal to the minimum flow rate among the learning flow rates, or the leak determination means may be provided for the gas combustion device. The ignition flow rate range set based on the ignition flow rate is stored, and when the target flow rate is within the ignition flow rate range after the elapse of the first period, it is determined that no gas leakage has occurred. In this case, the comparative flow rate may be set to be equal to the minimum flow rate of the learning flow rate outside the range of the ignition flow rate.

In the gas meter or the gas leak detection method according to the present invention, the ignition flow range may be set from the outside, or the ignition determination means may determine the ignition flow range before the first period. Is stored, and when a part of the learning flow rate is within the ignition flow rate setting range after the elapse of the first period, the ignition rate is set based on the learning flow rate at this time. The flow rate range may be set.

[0016] In the gas meter or the gas leak detection method of the present invention, the flow rate measuring means may measure the learning flow rate and the target flow rate for each and all of the one or more gas combustion appliances.

The gas meter or the gas leak detection method of the present invention may further include a flow rate storage means for storing at least the comparative flow rate.

In the gas meter or the gas leak detecting method according to the present invention, the leak judging means further includes a time measuring means for measuring time, and the leak judging means determines that the target flow rate is smaller than the comparative flow rate. The measurement of the second period may be started based on the measuring operation of the time measuring means.

The gas meter or the gas leak detecting method of the present invention further comprises a flow path shutoff means for shutting off the gas flow path when the leak judgment means judges that no gas has leaked. You may do so.

The gas meter or the gas leak detecting method according to the present invention further comprises communication terminal means for mutually communicating between the leak judging means and an external monitoring center, wherein the leak judging means detects a gas leak. When it is determined that there is a warning, warning information may be transmitted to the monitoring center via the communication terminal means.

In the gas meter or the gas leak detection method of the present invention, the length of the first period may be changeable, and the length of the second period may be changeable. .

[0022]

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 according to an embodiment of the present invention. Below,
A gas meter having a weighing mechanism using a flow sensor and a weighing mechanism using a fluidic element will be described. The gas leak detection method according to the embodiment of the present invention is embodied by the gas meter, and will be described below together.

The gas meter according to the present embodiment has a gas G
A measuring unit 10 having a piezoelectric membrane sensor 11 and a flow sensor 12 for measuring the flow rate of the gas, a control unit 20 for taking in the flow rate data measured by the measuring unit 10 and controlling the entire gas meter, , A shutoff valve 40 for shutting off a gas flow path (not shown) if necessary, and a shutoff valve 40
And a warning device 60 for issuing a warning when an abnormality such as a gas leak occurs. The piezoelectric film sensor 11 is for detecting fluidic oscillation (described later) of a fluidic element (not shown) in charge of detecting a flow rate in a large flow rate range, and the flow sensor 12 is for detecting a flow rate in a low flow rate range. It is for taking charge of. Although not shown, the gas meter includes, for example, a plurality of gas appliances (eg, a gas range, a gas heater, a gas heater, etc.) via a pipe (not shown).
Is connected.

The control unit 20 is configured using, for example, a microcomputer, and operates by executing a program stored in a ROM (Read Only Memory) (not shown) or the like.

The control unit 20 includes a measuring unit 10 (piezoelectric film sensor).
11, gas G based on the measurement result of the flow sensor 12)
Instantaneous flow rate Q_S1Flow rate calculation unit 21 for calculating
Instantaneous flow rate Q calculated by the flow rate calculation unit 21_S1Based on
Flow rate Q of gas G_S2Flow integration unit 2 for calculating
2 and the instantaneous flow rate Q calculated by the flow rate calculation unit 21 _S1
Leak to determine the state of gas G leakage
Setting unit 23, a leakage determination unit 23 and an external monitoring
Connect them so that they can communicate with each other.
And a communication terminal unit 24.

The flow rate calculating section 21 binarizes the flow rate signals S _R output from the piezoelectric film sensor 11 and the flow sensor 12 of the metering section 10, respectively, and outputs the instantaneous flow rate value based on one or both of these signals. _QS1 is calculated for each unit time (for example, one hour) and output to both the flow rate integrating unit 22 and the leak determining unit 23. The instantaneous flow rate Q _{S1 at} this time is, for example, the total flow rate consumed by a plurality of gas appliances (not shown) connected to the gas meter. Note that the present invention is not necessarily limited to such a case, and the flow rate calculation unit 21 may individually calculate the gas flow rate (individual flow rate) of each of the plurality of gas combustion devices, or may calculate both the total flow rate and the individual flow rate. May be calculated. The flow rate accumulating unit 22 includes a flow rate calculating unit 21
Instantaneous flow rate Q _S1 unit time outputted from (e.g. 1 hour) by integrating each interval calculates the integrated flow rate Q _S2 of the gas G, and outputs to the display unit 30. here,
The weighing unit 10 and the flow rate calculating unit 21 mainly correspond to a specific example of “flow rate measuring unit” in the present invention.

The leak judging section 23 takes in the instantaneous flow rate Q _S1 of the gas G calculated by the flow rate calculating section 21 at every unit time (for example, one hour) interval, and in the flow path (not shown) on the downstream side of the gas meter. In addition to determining the presence or absence of gas leakage,
In accordance with the result of this determination, drive control of the shut-off valve 40, issuance control of the alarm device 60, and the like are performed. Determining More specifically, the leakage determination unit 23, based on the instantaneous flow rate Q _S1 of the gas G which is output from the flow rate calculation unit 21 determines whether or not gas leakage has occurred, as a result, the gas leakage occurred when it outputs the interrupting signal S _K to the valve driving unit 50, and outputs a warning issued signal S _H to the alarm 60. At this time, the leak determination unit 23
At the same time as the output of the cutoff signal S _{K and the} like, the communication terminal 24
, A connection request signal S _Y is output. In response to the connection request signal S _Y , the communication terminal unit 24 connects the leak determination unit 23 and an external monitoring center via an electronic communication line (not shown) such as a telephone line, and The determination unit 23 transmits the warning information I to an external monitoring center via the communication terminal unit 24 or the like. At this time, the leak determination unit 23 also transmits the warning information I to the display unit 30 and causes the display unit 30 to display the warning information I. The warning information I includes, for example, various information such as the date and time when the supply of the gas G was cut off and the cutoff status. Here, mainly the leak determination unit 2
Reference numeral 3 corresponds to a specific example of “flow rate determining means” and “leakage determining means” in the present invention.

The display unit 30 is, for example, an LCD (Liquid Cry).
stal Display (liquid crystal display), for example, the integrated flow rate Q of the gas G output from the flow rate integrating unit 22.
_S2 is displayed. In addition, the display unit 30
For example, warning information I output from the leak determination unit 23 when a gas leak occurs is displayed.

The valve drive unit 50 detects a gas leak when a gas leak occurs.
Cut-off signal S output from the setting unit 23 _KAccording to the shut-off valve
40 to drive off the supply of gas G
I have. The alarm 60 is provided when the gas leakage occurs.
Alarm output signal S output from_HIssue an alarm according to
It is made to let. This alert, for example,
Signal to notify the abnormal situation such as gas leakage
It is. Here, mainly the shutoff valve 40 and the valve drive unit 5
0 corresponds to a specific example of “flow path blocking means” in the present invention.
Respond.

FIG. 2 shows a detailed configuration of the leak determination unit 23 shown in FIG. Leakage determination unit 23 fetches the instantaneous flow rate Q _S1 outputted from the flow rate calculation unit 21 (see FIG. 1), a control unit 25 for performing a series of gas leakage determination based on the instantaneous flow rate Q _S1 captured, A clock 26 for measuring time and a control unit 2
5 has a RAM (random access memory) 27 for storing the acquired flow rate data (such as the instantaneous flow rate Q _S1 ) and other various parameter values. here,
The clock 26 mainly corresponds to one specific example of “time measuring means” in the present invention, and the RAM 27 corresponds to one specific example of “flow rate storing means” in the present invention.

The control unit 25 takes in the instantaneous flow rate Q _S1 , monitors the instantaneous flow rate Q _S1 ,
Based on the information obtained from M27, it is determined that a gas leak has occurred when a predetermined condition described later is satisfied. When the control unit 25 determines that gas leakage has occurred, the control unit 25 sends a shut-off signal S to the valve driving unit 50.
_K, and outputs a connection request signal S to the communication terminal unit 24.
Outputs _Y, so that the outputs warning information I to the display unit 30 and the external monitoring center, and outputs a warning issued signal S _H relative to alarm 60. Hereinafter, the output operation of the above-described various signals of the control unit 25 when it is determined that the gas leakage has occurred is collectively referred to simply as “warning operation”. The details of the procedure for determining gas leakage by the control unit 25 and the operation of the control unit 25 at the time of the determination will be described later (FIG. 9).
To FIG. 12).

The RAM27 is, in addition to storing the instantaneous flow rate Q _S1 incorporated in the control unit 25 include the corresponding reference flow Q _K, compared flow rate Q _H, the upper limit instantaneous flow rate Q _U, the lower limit instantaneous flow rate Q _L of various Various parameter values such as flow rate data, learning period _TG , and continuation allowable time _TK2 are stored.

FIG. 3 shows a sectional structure of the measuring section 10 shown in FIG. The measuring section 10 includes a main body 70 having an inlet 71 for receiving the gas G and an outlet 72 for discharging the gas G. A partition 73 is provided in the main body 70.
Are provided, a first gas flow path 74 is formed between the partition wall 73 and the inlet section 71, and a second gas flow path 75 is formed between the partition wall 73 and the outlet section 72. An opening 76 is provided in the partition wall 73, and the above-described shutoff valve 40 (see FIG. 1) is provided in the first gas flow path 74 so as to close the opening 76. Further, a valve drive unit 50 (see FIG. 1) made of a solenoid or the like is fixed to the outside of the main body 70,
The plunger 91 of the valve driving section 50 penetrates the side wall of the main body 70 and is connected to the shutoff valve 40. A spring 77 is provided around the plunger 91 between the shutoff valve 40 and the main body 70, and the spring 77 urges the shutoff valve 40 toward the opening 76 side. During normal use,
The solenoid of the valve drive unit 50 is kept energized,
The shutoff valve 40 is separated from the opening 76.

In the second gas flow path 75, there is provided a nozzle 78 for passing the gas G received from the inlet 71 to generate a jet. A rectifying member 79 for adjusting the flow of the gas G is provided upstream of the nozzle 78. On the downstream side of the nozzle 78, a pair of side walls 80 and 81 forming an enlarged flow path are provided. A first target 82 is provided on the upstream side and a second target 83 is provided on the downstream side at predetermined intervals between the side walls 80 and 81. Outside the side walls 80 and 81, a pair of feedback flow paths 84 and 85 are formed for returning the gas G passing through the nozzle 78 to the ejection port side of the nozzle 78 along the outer peripheral portion of each side wall 80 and 81. A return guide 86 is provided. A pair of discharge passages 87 and 88 are formed between the outlets 72 of the feedback passages 84 and 85 by the back surface of the return guide 86 and the main body 70. A piezoelectric film sensor 11 for detecting a change in the direction in which the gas G flowing through the nozzle 78 flows is provided near the ejection port of the nozzle 78.
(Not shown in FIG. 3; see FIGS. 1 and 4) are provided with pressure guiding holes 89 and 90.

In the passage of the nozzle 78, the flow sensor 1
2 are provided. The flow sensor 12 is configured as, for example, a thermal flow sensor having a heat generating portion and two temperature sensors disposed before and after the heat generating portion.

FIG. 4 is an enlarged cross-sectional view of the main body 70 including the pressure guiding holes 89 and 90 in FIG. Body 7
The piezoelectric film sensor 11 is provided outside the bottom of the zero. In addition, the pressure guiding holes 89 and 90 are respectively provided with pressure guiding tubes 9.
One end of 5,96 is connected. These impulse lines 9
The other ends of the pressure sensors 5 and 96 are connected to pressure inlets of the piezoelectric film sensor 11, respectively. Then, the pressure difference between the pressure guiding hole 89 and the pressure guiding hole 90 is detected by the piezoelectric film sensor 11,
Fluidic oscillation is detected based on the change in the differential pressure. The pressure guiding tubes 95 and 96 and the piezoelectric film sensor 11 are covered by a case 97 fixed to the outside of the bottom of the main body 70.

Here, with reference to FIG. 2, FIG. 5 and FIG. 6, the procedure of the gas leakage determination in the control unit 25 of the leakage determination unit 23 will be described in order. FIG. 5 illustrates a series of gas flow rates processed by the control unit 25 during and after a learning period _TG described later, and FIG. 6 illustrates a period of the learning period _TG . It is for explaining the learning operation procedure of the control unit 25 and the operation timing related to the gas leakage determination of the control unit 25 after the lapse of the learning period _TG . In FIG. 6, (A) gas flow rate,
(B) Time measurement (clock count) for judging gas leakage, (C) Output of cut-off signal is shown, and the horizontal direction (arrow direction) in the figure represents the passage of time. In addition,
It is assumed that the gas G has not leaked during the learning period _{TG described} below.

1) Learning period T_GReference flow within the period
Quantity Q_KUpdate processing First, the control unit 25
Consumption of gas G by a customer within a predetermined period
Consumption data (instantaneous flow Q_S1) The unit time
(For example, one hour). Where
During the “predetermined period”, the customer's house where the gas meter was installed
G consumption data (instantaneous flow rate Q _S1)
Customer gas consumption (instantaneous flow Q_S1Distribution state)
Learning period T for learning_GIt is. This learning period T
_GMust be set arbitrarily before installing the gas meter.
Can be. Learning period T in the present embodiment_GIs like
It is one year. In the RAM 27,
Any number (for example, n) of reference flow rates Q_K(Q_K= Q_K1,
Q_K2, Q_K3... Q_Kn-1, Q_Kn) Is stored. Study
Study period T_GBefore the start of the process, these reference flow rates Q
_K(Q_K= Q_K1~ Q_Kn) Is the default setting
If the upper limit instantaneous flow Q_UFlow rate value (for example,
100L (liter) / h (hour); see FIG. 7)
Has been recorded. Here, the learning period T_GHowever, in the present invention,
Learning period T corresponding to one specific example of “first period”_Gof
Instant taken into the control unit 25 during the period
Flow Q_S1Is a specific example of "learning flow rate" in the present invention.
Corresponding.

The control unit 25 controls the learning period T_GPeriod
The instantaneous flow rate Q_S1And reference flow Q_K
Are compared with each other.
Quantity Q _KSome of them (eg Q_K1) To the instantaneous flow rate Q_S1
Is updated to the value of At this time,
Reference flow rate Q_KOf the reference flow rate Q_KQ of _K1
To Q_KnAre performed in order. In addition,
Reference flow rate Q in control section 25_KUpdate procedure details
Details will be described later (see FIG. 10).

2) Learning period T_GFlow in the period of
Quantity Q_HSetting of the above update process in the learning period T_GWithin the period
By performing continuously, any number (for example, n) of
Reference flow rate Q_K(Q_K1~ Q_Kn) Is the instantaneous flow rate Q_S1Update from time to time
And learning period T_GAt the passage of the reference flow rate Q
_K(Q_K1~ Q_Kn) Is Q_K1To Q_KnIt will increase in order to
(Q_K= Q_K1<Q_K2<Q_K3・ ・
・ Q_Kn-1<Q_Kn). That is, the reference flow rate Q at this time_K1
Is the learning period T_GInstantaneous flow rate measured during the period
Q_S1Becomes the minimum flow rate. Here, the control section
25 is the learning period T_GBy the consumer during the period of
The reference flow rate Q_K1And select this
Quasi flow Q_K1Flow rate Q so that it becomes equal to the value of_HThe value of
Set. This "comparison flow Q_H"Means the learning period T_GSutra
After a short time, the control unit 25 makes a judgment of gas leakage.
This is an indicator of the situation. In the following, the above learning period
Interval T_GInstantaneous flow rate Q during the period_S1Standard flow from acquisition of
Quantity Q_KRenewal, reference flow Q_K1Through selection of the comparison flow Q_H
A series of actions leading up to the setting of
Operation ". The control unit 25 controls the comparative flow rate Q_H
After setting this, the comparative flow rate Q_HTo other reference flow rates Q_K
(Q_K2~ Q _Kn) Is stored in the RAM 27. In addition,
At this time, the other reference flow rate Q _K(Q_K2~ Q_Kn)
It is not necessary to memorize it. Comparative flow rate in RAM27
Q_HIs stored in the control unit 25 at the time when
A series of learning operations is completed in the learning period T_GAfter
The preparation for making a determination of gas leakage is completed in.

3) Learning period T_GTarget flow after the passage of
Quantity Q_TAcquisition of gas and judgment of gas leakage Learning period T_GAfter the time elapses, the control unit 25
Is a gas consumption day accompanying the consumption of gas G by consumers.
(Instantaneous flow rate Q_S1). In the following,
Learning period T_GTo the control section 25 after
Instantaneous flow rate Q_S1To "Target flow rate Q_T"
It shall be. The control unit 25 controls the target flow rate Q_TAnd ratio
Comparative flow rate Q_HAnd the target flow rate Q_TIs the comparative flow rate Q_HYo
Is smaller (Q_T<Q_HThe gas flow rate Q shown in FIG.
_M= Q_T), Other than the consumption of gas G by the consumer
Is determined to have detected the gas flow rate generated by
Target flow rate Q at_T(= Q_M) Is due to gas G leakage
Judge that there is a possibility. At this time,
The roll section 25 has a target flow rate Q_T(= Q_M) Depending on
Output from the clock 26 simultaneously with the detection of the flow pulse
Time measurement based on the clock signal
6) (clock count START; FIG. 6).
reference). Then, the control unit 25 controls the clock cow.
Time elapsed since the start (clock count time
T_C2) Is the permissible continuation time T_K2(For example, T _K2= 24 hours)
(T_C2≧ T_K2) At this time
Target flow rate Q_T(= Q_M) Is due to gas G leakage
And the shut-off signal S to the valve drive unit 50 is determined._KOutput
(See FIG. 6). Note that the above clock count time
T _C2Is the learning period T_GArbitrarily before
Can be In the following, the comparative flow rate Q as described above_H
Of safety actions related to gas leak determination based on
Also referred to as "blocking." Here, the continuation allowable time T_K2However, the present invention
Corresponds to a specific example of “second period”.

On the other hand, when the target flow rate Q _T is equal to or greater than the comparative flow rate Q _H (Q _T ≧ Q _H ; when the flow rate Q _A = Q _T shown in FIG. 6), the control unit 25 continues the conventional operation. A security operation corresponding to time recognition cutoff or large flow duration time recognition cutoff described later (see FIG. 7) is performed. Incidentally, gas meter according to the present embodiment, according to the flow rate range belongs target flow rate Q _T, said learning rate comparison blocking, a plurality of security operations such as recognition blocking and high flow duration recognized cutoff duration Do. The contents of a series of security operations corresponding to the respective flow ranges of the gas G will be described later (see FIG. 7).

As described above, during the learning period _TG , the reference flow rate Q _K1 which is the minimum flow rate among the reference flow rates Q _K.
Set the value as the value of the comparison flow Q _H, after elapse of the learning period T _G, the target flow rate was measured Q _T is compared flow rate Q _H
When a gas flow state smaller than (Q _T <Q _H ) is detected for a predetermined period of continuous allowable time T _K2 ,
Since it is determined that a gas leak has occurred, it is possible to avoid a malfunction of a warning operation, which has been conventionally regarded as a problem, and to improve reliability in determining a gas leak. Because, after the learning period _TG elapses, the comparative flow rate Q _H
Target flow rate Q _T less than is because unlikely to occur due to factors other than the gas leakage. In addition, with the improvement of the reliability of the gas leak determination, the time until the gas leak is finally determined (permissible continuation time T _K2 ) can be shortened. Can be found early.

Here, with reference to FIG. 7, a series of security operations of the gas meter according to the present embodiment will be sequentially described for each gas G flow area. In the following, the security operation of the control unit 25 (see FIG. 2) corresponding to each flow rate region will be mainly described. The vertical axis in the figure is the target flow rate Q _T
(L / h), and each flow area (flow area A to flow area C) shown as a different area corresponds to a different security operation of the gas meter.

1) Flow rate range A The flow rate range A is such that the target flow rate Q _T is equal to or larger than a preset upper limit instantaneous flow rate Q _U (for example, Q _U = 100 L / h) (Q _T ≧ Q _U ). This is a large flow range. In the flow rate range A, for example, a time (large flow rate safe duration time T _D ) that can be used continuously corresponding to a specific flow rate is predetermined (for example, when Q _T = 150 L / h, T _D = 720 hours), at the time when the usage time has reached the large flow safety duration T _D of the gas G with such a flow rate, the control unit 25 performs a warning operation (high flow duration recognition cutoff). In the flow rate range A, in addition to the interruption of the recognition of the large flow rate duration as described above, for example, when the target flow rate Q _T (total flow rate or individual flow rate) reaches the upper limit instantaneous flow rate Q _U , the control unit 25 immediately operates. May be performed (recognition interruption of total flow rate, interruption of recognition of individual flow rate).

[0047] 2) flow rate range B flow rate range B, the subject flow rate Q _T is compared flow rate Q at _H or higher and less like flow area than the upper limit instantaneous flow rate Q _U (Q _H
≦ Q _T <Q _U ). In the flow rate range B, the control unit 25 performs a security operation substantially similar to, for example, the conventional duration recognition cutoff. That is, the control unit 2
5, the use time of the gas G with the flow belonging to the flow rate range B (clock count time T _C1) is measured, a clock count time T _C1 of this time continued permissible time T _K1 (e.g., T _K1 = 720 hours) At the time (T _C1 ≧ T _K1 ), it is determined that a gas leak has occurred, and a warning operation is performed (see FIG. 16).

[0048] 3) flow rate region C flow rate range C, the subject flow rate Q _T is preset lower limit instantaneous flow rate Q _L (e.g., Q _L = 3L / h) greater than, and less than comparative flow rate Q _H Flow rate range (Q
_L <Q _T <Q _H ). The lower limit instantaneous flow rate Q _L is, for example, a general flow sensor (e.g., flow sensor 12 of the measuring unit 10 is a gas meter according to the present embodiment; FIG. 1
Is the flow rate corresponding to the lower limit of the measurable flow rate range. The lower limit instantaneous flow rate Q _L may be changed at any time depending on the measurable range of the flow sensor to be used. In the flow rate range C, the control unit 25 performs a security operation corresponding to the learning flow rate comparison cutoff.

[0049] 4) flow rate range D The flow rate range D is a small flow rate range, such as object flow Q _T is less than the lower limit instantaneous flow rate _{Q L (Q T ≦ Q L} ).
The flow rate in the flow rate range D belongs to a range equal to or lower than the lower limit of the measurable flow rate range of a general flow rate sensor, and largely includes a measurement error or the like of the flow rate sensor. For this reason, for example, the control unit 25 is set so as not to perform any security operation in the flow rate range D.

It should be noted that Q _{K1 to} Q _Kn in the figure represent the reference flow rate Q _K. In FIG. 7, for example, the reference flow rate Q _K1
~ Q _Kn-1 is smaller than the upper limit instantaneous flow rate Q _U and the reference flow rate Q
_Kn represents the case larger than the upper limit instantaneous flow rate Q _U.

FIG. 8 is for explaining the contents of a series of security operations for each flow rate range in a conventional gas meter as a comparative example. Flow area A to flow area C shown in FIG.
Correspond to the respective flow rate ranges described in FIG.

As described above, in FIG. 7 and FIG. 8, in the flow rate range B, in order to make a determination regarding gas leakage (interruption of recognition of duration), a long period corresponding to the permissible duration T _K1 (for example, T _K1 = 720 hours (30 days). On the other hand, in the flow rate range C, a short period (for example, T _K2) corresponding to the continuation allowable time T _K2 is required in order to make a determination regarding gas leakage (learning flow rate comparison cutoff). = 24 hours (1 day)). For this reason, the control unit 25 executes the security operation based on the learned flow rate comparison cutoff, and particularly, the flow rate (target flow rate Q _T ) belonging to the flow rate range C.
Is measured, the time required for gas leak determination is reduced.

Next, the operation of the gas meter according to the present embodiment will be described.

First, referring to FIGS. 1, 3 and 4,
The basic operation related to the flow measurement and display of the gas meter will be described. In FIG. 3, the gas G received from the inlet 71 of the measuring unit 10 is supplied to the first gas flow path 7.
4. The nozzle 78 passes through the opening 76, the second gas flow path 75, and the rectifying member 79 in this order. The gas G that has passed through the nozzle 78 becomes a jet and is jetted from the jet port. The gas G spouted from the spout flows along one side wall due to the Coanda effect. Here, it is assumed that the flow firstly flows along the side wall 80. The gas G flowing along the side wall 80 is further returned to the ejection port side of the nozzle 78 through the feedback channel 84 and is discharged from the outlet 72 through the discharge channel 87. At this time, the direction of the gas G ejected from the nozzle 78 is changed by the gas G flowing through the feedback channel 84, and the gas G flows along the other side wall 81 this time. This gas G is further supplied to the feedback channel 85.
Is returned to the ejection port side of the nozzle 78 through the discharge path 88.
Through the outlet 72. Then, the nozzle 78
This time, the direction of the jetted gas G is changed by the gas G flowing through the feedback flow path 85, and the gas G flows again along the side wall 80 and the feedback flow path 84. By repeating the above operation, the nozzle 78
The gas G that has passed through the pair of feedback channels 84 and 8
Fluidic oscillation which alternately flows 5 is performed. The frequency and cycle of this fluid oscillation correspond to the flow rate, are detected by the piezoelectric film sensor 11 (see FIG. 4) and output as the flow rate signal S _{R1, and} are calculated by the flow rate calculation section 21 of the control section 20 (see FIG. 1). Is input to

On the other hand, the flow sensor 12 generates a temperature difference generated between two temperature sensors (not shown) according to the flow rate of the gas flowing through the heat generating portion (not shown) at a constant current or constant power. Is output as a flow rate signal and input to the flow rate calculation unit 21.

In FIG. 1, when the flow rate is in a large flow rate range suitable for measurement by the fluidic element, the flow rate calculation section 21 uses the flow rate signal S _R1 from the piezoelectric film sensor 11 to measure the flow rate by the flow sensor 12. When the flow rate is in the small flow rate range suitable for the above, the instantaneous flow rate Q _S1 of the gas G is calculated using the flow rate signal S _R2 from the flow sensor 12. Specifically, when using the piezoelectric film sensor 11, the flow rate calculation unit 21 generates a pulse based on the flow rate signal S _R1 from the piezoelectric film sensor 11,
The number of pulses per unit time is counted to determine the frequency of the fluidic oscillation, and this frequency is used as the instantaneous flow rate Q _S1
Convert to On the other hand, when the flow sensor 12 is used,
The number of pulses per unit time of the flow rate signal S _R2 from the flow sensor 12 is counted to determine the instantaneous flow rate Q _S1 . When the flow rate is in an area where the large flow rate area and the small flow rate area intersect, the flow rate calculation unit 21 may calculate the flow rate from one of the outputs, or may calculate the flow rate using both outputs ( for example by like) taking an average value may be calculated instantaneous flow rate Q _S1. Alternatively, as shown in JP-A-3-96817, the measurement value of the flow sensor 12 may be calibrated based on the measurement value of the output from the piezoelectric film sensor 11.

The instantaneous flow rate Q _S1 calculated by the flow rate calculation section 21 is output to the flow rate integration section 22 and also to the leak determination section 23. Flow rate integration unit 22 based on the instantaneous flow rate Q _S1 taken from the flow rate calculation unit 21 calculates the integrated flow rate Q _S2, and displays and outputs this to the display unit 30.

Next, with reference to FIGS. 1 and 2 and the flowcharts shown in FIGS. 9 to 12, the operation of the gas meter for detecting gas leakage will be described. In the following, the operation of the control unit 25 of the leak determination unit 23 related to gas leak detection during and after the learning period _TG will be described in order.

[0059] 1) Operation control section 25 of the control unit 25 in the period of learning period T _G, first, the instantaneous flow rate Q of the learning period T (see FIG. 9 during the period of _G), the gas G from the flow rate calculation unit 21 _S1 is obtained (step S101). Next, n reference flow rates Q _K stored in the RAM 27 in advance.
_{(Q K1, Q K2, Q} K3 ··· Q Kn-1, Q Kn) Q of the _K1
Is compared with the value of the instantaneous flow rate Q _S1 , and when the two have a predetermined relationship, the value of the reference flow rate Q _K1 is updated to the value of the instantaneous flow rate Q _S1 . Details regarding the procedure of the update processing A at this time will be described later (see FIG. 10). The above-described updating process of the reference flow rate Q _K is continuously performed within the learning period _TG , and finally, n reference flow rates Q _K (Q _K1 ,
Q _K2 , Q _K3 ... Q _Kn-1 , Q _Kn ) to the instantaneous flow rate Q
_It is updated to _S1 at any time (step S102). At this time, the updated n reference flow rates Q _K are stored in the RAM 27. Next, the reference flow rate Q _K updated by the update processing A
To set the value of the minimum flow Q _K1 of a value of the comparison flow Q _H (step S103). Next, the comparative flow rate Q _{H is set} to R
It is stored in the AM 27 (step S104). At this point, the control unit 25 during the learning period _TG
Learning operation is completed.

2) Reference flow rate Q_KHere, the reference flow rate Q described above is used._KWhen performing an update process (Figure
10), the control unit 25 first obtains
First instantaneous flow rate Q_S1(Learning period T_GGet immediately after start
First instantaneous flow rate; for example, Q_S1= 30L / h)
Reference flow rate Q_K1(For example, initial setting Q_K1= 100L / h)
(Step S201), and_S1≤Q_K1in the case of
(Step S201Y) includes the reference flow rate Q_K1The value of
Instantaneous flow rate Q_S1(Step S202).
By this update processing, the reference flow rate Q_K1As the value of
30 L / h is registered. Next, the acquired second instantaneous flow
Quantity Q _S1(Learning period T_GSecond after the start of
Instantaneous flow rate; for example, Q_S1= 50L / h) and the above criteria
Flow Q_K1(Q_K1= 30L / h registered)
(Step S201), Q_S1> Q_K1If (step
S201N) is followed by a second instantaneous flow rate Q_S1And reference flow
Quantity Q_K2(For example, initial setting Q_K2= 100 L / h)
Are compared (step S203). At this time, Q_S1≤Q_K2of
In this case (step S203Y), the reference flow rate Q_K2The value of
Second instantaneous flow rate Q_S1(Step S20)
4). By this update processing, the reference flow rate Q_K2As the value of
For example, 50 L / h is registered. Next, the acquired third
Instantaneous flow Q_S1(Learning period T_GThird after the start of
Obtained instantaneous flow rate; for example, Q_S1= 70L / h) and standard
Flow Q_K1(Q_K1= 30L / h), Q
_K2(Q_K2= 50L / h), Q_K3(example
If the initial setting Q_K3= 100L / h)
Compare (Steps S201, S203, S205)
_K1<Q_K2<Q_S1≤Q_K3(Step S201N,
Step S203N, step S205Y) include the reference flow
Quantity Q_K3To the third instantaneous flow rate Q_S1Update to the value of
Step S206). By this update processing, the reference flow rate Q_K3of
For example, 70 L / h is registered as the value.

According to such a procedure, the initial setting value
Another reference flow rate Q having for example 100 L / h_K4~ Q_KnTo
The same updating process is performed for the learning period T_GWithin
Instantaneous flow rate Q of gas G obtained in_S1Based on
Reference flow rate Q_K(Q_K1, Q _K2, Q_K3... Q_Kn-1, Q
_Kn) Are sequentially updated. Finally, these n reference streams
Quantity Q_KIs Q_K1<Q_K2<Q_K3... Q_Kn-1<Q_Knconnection of
. That is, update
When processing is completed (learning period T_GFlow rate at the time of
Q_K1Is the learning period T_GGas measured within the period
Instantaneous flow Q of G _S1Of the minimum flow rate
You.

3) Operation of Control Unit 25 After Elapse of Learning Period _TG After the elapse of the learning period _TG (see FIG. 11), the control unit 25 first sends the target flow rate Q of gas G from the flow rate calculation unit 21. _T (instant flow rate Q _S1 ) is acquired (step S3)
01). Next, compared with the comparative flow rate Q _H and the target flow rate Q _T (step S302), the target flow rate Q _T is Q _L (lower instantaneous flow rate; see FIG. 7) <case is within the range of Q _T <Q _H In (Step S303Y), it is determined that there is a possibility of gas leakage, and time measurement (clock counting) is started (Step S304). Then, the elapsed time (clock count time T _C2 ) from the start of the clock count is equal to or longer than the continuation allowable time T _K2 (for example, T _K2 = 24 hours).
_{If C2} ≧ T _K2 ) (step S305Y),
When T _C2 = T _K2 , a warning operation is executed (step S306). Incidentally, if T _C2 <T _K2 (step S305N), it is determined that no gas leakage has occurred, and the operation of acquiring the target flow rate Q _T again (step S30)
Return to 1).

It should be noted, compared with the comparative flow rate Q _H interest rate Q _T (step S302), the target flow rate Q _T is Q _L <Q _T
<When not belonging to the range of Q _H (step S303N;
In B), the operation shifts to the security operation shown in FIG. That is, when the target flow rate Q _T is equal to or more than Q _U (the upper limit instantaneous flow rate; see FIG. 7) (Q _T ≧ Q _U ) (step S401Y), the recognition of the large flow duration time or the recognition of the total flow rate is interrupted.
Performs security operations such as individual flow rate recognition cutoff. On the other hand, when the target flow rate Q _T falls within the range of Q _H ≦ Q _T <Q _U (step S401N, step S402Y), a security operation such as interruption of recognition of the duration is performed. The target flow rate Q
_T be a less than the lower limit instantaneous flow rate _{Q L (Q T ≦ Q L} ); (step S402N C), the acquisition operation of the target flow rate Q _T (FIG. 11; step S301) to return to.

[0064] As described above, according to the gas meter or the gas leakage detection method according to this embodiment, on the basis of the comparison the flow rate Q _H learned within a period of learning period T _G, after a learning period T _G When a gas flow state in which the measured target flow rate Q _T is smaller than the comparative flow rate Q _H (Q _T <Q _H ) is detected over the allowable continuous time T _K2 ,
Since it was determined that gas leakage had occurred, it was possible to avoid malfunctioning of the warning operation, which has been a problem in the past,
It is possible to improve reliability regarding detection of gas leakage. In addition, with the improvement of the reliability of the gas leak detection, the time (continuous allowable time T _K2 ) until it is finally determined that the gas leak has occurred can be shortened.
An abnormal situation such as gas leakage can be found at an early stage.

Also, in the present embodiment, the leak determination unit 23
When the control unit 25 detects a gas leak state, the warning information I is transmitted to the external monitoring center via the communication terminal unit 24. An abnormal situation such as a generated gas leak can be confirmed at an early stage, and this situation can be dealt with at an early stage.

The above-mentioned parameter values such as the learning period _TG and the continuation allowable time T _K2 are based on the type, type, number of installations, installation status, usage status, and gas G It can be changed appropriately according to the consumption frequency and the like. At this time, each parameter value may be changed directly by a worker going to the installation site of the gas meter, or a communication process (for example, data transmission by a telephone line or the like) from a monitoring center via the communication terminal unit 24 ) May be performed.

In this embodiment, when the occurrence of gas leakage is detected, a series of warning operations, ie, (1)
Display of the warning information I on the display unit 30, (2) interruption of the supply of gas G by driving the shutoff valve 40, (3) issuing of an alarm by the alarm 60, (4) of the alarm information I to the external monitoring center. The transmission (including the output of the connection request signal S _Y ) is performed, but is not necessarily limited to this. For example,
Execution or non-execution of each of the above operations can be set arbitrarily, and when the occurrence of gas leakage is detected,
Only some of the various operations described above may be performed as needed. However, in order to ensure the safety of the consumer using the gas G, it is preferable to perform the above-described series of operations.

In the present embodiment, the control unit 20 includes the communication terminal unit 24, and the gas meter has a communication function. However, the present invention is not limited to this, and the gas meter does not have the communication function. It may be. However, in order to promptly report the occurrence of an abnormal situation such as gas leakage to the monitoring center or to change various parameter values such as the learning period _TG remotely from the monitoring center, the gas meter needs to communicate with the monitoring center. It is preferable to have a function.

[0069] In the present embodiment, as shown in FIG. 7, on the basis of the flow rate range of interest rate Q _T acquired in after a learning period T _G belongs, these various corresponding to each flow rate region Although the security operation (for example, learning flow rate comparison cutoff) is performed, it is not necessarily limited to this. For example, as shown in FIG. 13, when the ignition flow Q _Z of the gas-fired device connected to the gas meter (the flow due to the small fire for ignition in the gas appliance) is known in advance, the ignition flow Q _Z pilot flame flow area based on leave artificially registered in advance from the outside (flow rate region E1 and flow zone E2 in the figure), when the target flow rate Q _T acquired in after a learning period T _G belongs to pilot flame flow rate range May not perform the security operation. In such a case, it is possible to quickly and accurately perform a gas leak determination (no gas leak has occurred) when the gas appliance is in a spark ignition state. Note that the above-mentioned registration of the “ignition flow rate Q _Z ” may be performed by a gas company or the like at any time (for example, during or before or after the learning period _TG ).

Here, the above-mentioned ignition flow rate range is, for example, a flow rate range represented by an ignition flow rate Q _Z ± x% (for example, x = 5). In FIG. 13, for example, two gas appliances,
That is, a gas appliance A (for example, a gas range) having an ignition flow Q _Z1 and a gas appliance B (for example, a gas heater) having an ignition flow Q _Z2 are connected to the gas meter (Q _Z1 <Q _Z2 ). pilot flame flow rate range corresponding to the pilot flame flow (Q _Z1, Q _Z2) (flow rate region E1 = Q _Z1 ± x%, flow rate range E2 = Q _Z2 ± x%) represents a case where it is registered. Also, for example, Q _K1 , Q of the reference flow rate Q _{K
The case where K2} ( _QK1 < _QK2 ) belongs to the ranges of the flow rate range E1 and the flow rate range E2, respectively.

In the above case, an ignition flow area (flow area E1, flow area E2) is individually provided based on the ignition flow rate (Q _Z1 , Q _Z2 ) of each of the gas appliances A and B. However, in addition to this, the ignition flow rate range may be set based on the total value of both ignition flow rates (Q _Z12 = Q _Z1 + Q _Z2 ; not shown). In such a case,
Gas leak determination (no gas leak has occurred) when both gas appliances A and B are in a spark ignition state can be performed more quickly. Of course, even when three or more gas combustion devices are connected to the gas meter, the ignition flow region may be registered based on the individual ignition flow amount or the total ignition flow amount of these gas combustion devices. The operation of the gas meter in the flow rate range A to the flow rate range D shown in FIG. 13 is the same as that shown in FIG.

Incidentally, the registration of the ignition flow area as described above is performed as follows.
Must be done artificially from outside
There is no. For example, the learning period T_GIn the stage before
Pre-ignition flow rate setting range (for example, 5 L / h ≦ Q_Z≤52
L / h), and the learning period T_GWithin the period of
And updated reference flow Q_KIs within the above range
The reference flow rate Q at this time_KOf the ignition range based on the
The recording may be performed automatically. For example, the criteria
Flow Q_KQ of_K1, Q_K2Is within the ignition flow rate setting range.
In this case, as shown in FIG.
And flow rate range E1 = Q _K1± x%, flow area E2 = Q_K2± x%
It will be registered. In such a case, the reference flow
Q_KMinimum flow outside the ignition flow setting range
That is, the reference flow rate Q_K3Is the comparative flow rate Q_HRegistered as a figure
14 corresponds to the learning flow rate comparison cutoff.
Security operation is performed. In such a case
In the above case (registration of ignition flow area
In this case, the same effect as in the case of Note that this
Implementation or non-execution of such automatic registration of the ignition flow area is optional.
You may make it selectable at will. Flow rate shown in FIG.
The operation of the gas meter in the region A to the flow region D is shown in FIG.
This is the same as when

The setting of each parameter value such as the above-mentioned ignition flow area (including the individual ignition flow rate and the total ignition flow rate) and the ignition flow rate setting range is also performed by setting the parameter values such as the learning period _TG and the allowable continuation time T _K2. As in the case of the setting described above, the worker may go to the site (the place where the gas meter is installed) or perform the communication processing from an external monitoring center.

As described above, the present invention has been described with reference to some embodiments. However, the present invention is not limited to these embodiments, and various modifications are possible. For example, in the above embodiment, a gas meter using both a fluidic element and a flow sensor has been described, but the present invention is not limited to this. For example, a gas meter using only a fluidic element, The present invention is also applicable to one using only a sensor.

In the above embodiment, the gas meter has a learning function for performing a series of learning operations.
The present invention is not necessarily limited to this. For example, the learning function may not be provided. In such a case, for example, the type of gas appliance connected to the gas meter, after the gas company or the like in consideration of the installation number or the like is artificially set the flow rate was selected as a comparative flow rate Q _H, the above-described The same gas leak determination operation as in the case of the embodiment is performed. Also in this case, the same effect as in the above embodiment can be obtained. Incidentally, also it may also be directly carried out by dispatching workers, etc. to the installation site of the gas meter setting operation of comparing the flow rate Q _H in this case,
Or you may make it perform indirectly using communication processing.

[0076]

As described above, according to the gas meter according to any one of claims 1 to 13, or according to the gas leak detection method according to any one of claims 14 to 26, The comparison flow rate is set based on the learning flow rate of the fuel gas measured in the first period, and the second flow is set such that the target flow rate of the fuel gas measured after the lapse of the first time period is smaller than the comparison flow rate. Is determined to have occurred when the gas flow has continued over the period, the comparison flow rate can be appropriately set so as to reflect the gas consumption situation of the consumer during the first period.

In particular, according to the gas meter described in claim 2 or the gas leak detection method described in claim 15, the comparative flow rate is set to be equal to the minimum flow rate among the learning flow rates. The fuel gas consumption state in which the target flow rate of the fuel gas measured after the elapse of the period is smaller than the comparative flow rate may be due to a factor other than the consumption of the fuel gas by the consumer, that is, a gas leak. high. For this reason, it is possible to avoid the malfunction of the warning operation, which has been conventionally regarded as a problem, and to improve the reliability regarding the detection of gas leakage. In addition, with the improvement of the reliability of the gas leak detection, the second period until the gas leak is finally determined can be shortened. Can be found in

According to the gas meter described in claim 3 or the gas leak detection method described in claim 16, after the first period elapses, the ignition rate range is set based on the ignition rate of the gas-fired equipment. In the above, when the target flow rate is within the ignition flow rate range, it is determined that gas leakage has not occurred. Therefore, in this case, determination of gas leakage (no gas leakage has occurred) can be performed more quickly.

Further, according to the gas meter of the fourth aspect or the gas leak detecting method of the seventeenth aspect, the comparative flow rate is set to be equal to the minimum flow rate of the learning flow rate outside the range of the ignition flow rate. Therefore, also in this case, similarly to the case described in claim 2 or claim 15, it is possible to improve the reliability of gas leak detection, and to detect an abnormal situation such as gas leak at an early stage. it can.

According to the gas meter described in claim 6 or the gas leak detection method described in claim 19, the ignition flow rate setting range for setting the ignition flow rate range stored before the first period is set. Based on the learning flow at this time, when a part of the learning flow is within the ignition flow setting range after the first period, the ignition flow is set. The range can be registered automatically.

According to the gas meter described in claim 11 or the gas leak detection method described in claim 24, warning information is transmitted to an external monitoring center when the gas flow path is cut off. A gas company or the like in the monitoring center can confirm an abnormal situation such as a gas leak occurring at a customer's house at an early stage, and can respond to this situation at an early stage.

According to the gas meter of the twelfth aspect or the gas leak detecting method of the twenty-fifth aspect, the length of the first period can be changed. The length of the first period can be adjusted accordingly.

Further, according to the gas meter described in claim 13 or the gas leak detection method described in claim 26, the length of the second period can be changed. The length of the second period can be adjusted accordingly.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating a detailed configuration example of a control unit illustrated in FIG.

FIG. 3 is an enlarged cross-sectional view illustrating a main structure of a measuring unit illustrated in FIG.

FIG. 4 is an enlarged cross-sectional view illustrating a part of a main part structure of a measuring unit illustrated in FIG. 3;

FIG. 5 is a diagram for explaining a series of gas flow rates processed by a control unit within a learning period and after the learning period has elapsed.

FIG. 6 is a timing chart for explaining a series of gas leak determination methods in the gas meter shown in FIG.

FIG. 7 is a gas flow area diagram for explaining a series of security operations of the gas meter shown in FIG.

8 is a gas flow area diagram for explaining a series of security operations of a conventional gas meter as a comparative example with respect to the gas meter shown in FIG.

FIG. 9 is a flowchart illustrating a learning operation of a control unit during a learning period.

FIG. 10 is a flowchart illustrating an operation of updating a reference flow rate of a control unit during a learning period.

FIG. 11 is a flowchart illustrating a gas leak detection operation of a control unit after a lapse of a learning period.

FIG. 12 is a flowchart for explaining another gas leak detection operation of the control unit after a lapse of a learning period.

FIG. 13 is a gas flow area diagram for describing a security operation as a modification example of a series of security operations of the gas meter according to the present embodiment.

FIG. 14 is a gas flow area diagram for explaining a security operation as another modified example of a series of security operations of the gas meter according to the present embodiment.

FIG. 15 is a timing chart for explaining a series of gas leak detection methods in a conventional gas meter.

FIG. 16 is a timing chart for explaining a series of gas leak detection methods in a conventional gas meter.

FIG. 17 is a timing chart for explaining a problem in a conventional gas meter gas leak determination method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Measurement part, 11 ... Piezoelectric film sensor, 12 ... Flow sensor, 20 ... Control part, 21 ... Flow rate calculation part, 22 ... Flow rate integration part, 23 ... Leakage determination part, 24 ... Communication terminal part, 25 ... Control part, 26 clock, 27 RAM, 30 display unit, 40 shut-off valve, 50 valve drive unit, 60 alarm
G: Gas, I: Warning information, _SH : Warning signal, _SK :
Cutoff signal, S _Y … Connection request signal, T _C2 … Clock count time, T _K2 … Permissible continuation time, _TG … Learning period, _QS1
Instantaneous flow rate, Q _S2 ... integrating flow rate, Q _K ... standard flow rate, Q _H ... comparative flow, Q _L ... lower instantaneous flow rate, Q _T ... target flow rate, Q _U
... Upper limit instantaneous flow rate, Q _Z ... Fire flow rate.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) G08B 21/16 G08B 21/16 (72) Inventor Mamoru Suzuki 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Inside Gas Co., Ltd. (72) Inventor Shinichi Sato 1-5-20 Kaigan, Minato-ku, Tokyo Inside Tokyo Gas Co., Ltd. (72) Inventor Mitsunori Komaki 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Inventor Kenchi Kobayashi 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Inventor Ken Takeshiro 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Inventor Kenichiro Yuasa 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. F-term (reference) 2F030 CA04 CA10 CC13 CE25 CF05 CF11 2G067 AA14 BB11 CC04 DD04 5C086 AA02 BA11 CB11 DA01 DA08 EA13 EA40

Claims (26)

[Claims] 1. The method according to claim 1, wherein 1 or 2 is set within a first period.
The learning flow rate of the fuel gas consumed by the above gas combustion equipment is measured every unit time, and the target of the fuel gas consumed by the one or more gas combustion equipment after the elapse of the first period is measured. A flow rate measuring means for measuring a flow rate per unit time; and setting a comparison flow rate based on the learning flow rate when the first period has elapsed, and comparing the target flow rate after the first period has elapsed with the comparison flow rate. A flow rate determining means for determining whether or not the target flow rate is smaller than the comparative flow rate after a lapse of the first period based on a determination result by the flow rate determining means; And a leakage determining means for determining that gas has leaked in the gas flow path when the gas meter has continued for a period of time. 2. The gas meter according to claim 1, wherein the comparative flow rate is set to be equal to a minimum flow rate among the learning flow rates. 3. The leak determining means stores an ignition flow range set based on the ignition flow of the gas-fired device, and after the first period, the target flow is determined by the ignition flow. 2. When it is within the range, it is determined that there is no gas leakage.
The described gas meter. 4. The gas meter according to claim 3, wherein the comparative flow rate is set to be equal to a minimum flow rate of the learning flow rate outside the range of the ignition flow rate. 5. The gas meter according to claim 3, wherein the ignition flow range is set from outside. 6. The leak determination unit stores an ignition flow setting range for setting the ignition flow range before the first period, and when the first period has elapsed, 5. The method according to claim 3, wherein, when a part of the learning flow rate is within the ignition flow rate setting range, the ignition flow rate range is set based on the learning flow rate at this time. Gas meter. 7. The flow rate measuring unit according to claim 1, wherein the learning flow rate and the target flow rate are measured for each of the one or more gas combustion devices and the entirety thereof. 2. The gas meter according to claim 1. 8. The gas meter according to claim 1, further comprising a flow rate storage means for storing at least the comparative flow rate. 9. The leak determining means further includes a time measuring means for measuring time, and the leak determining means starts the time measuring means from a point in time when it is determined that the target flow rate is smaller than the comparative flow rate. The gas meter according to any one of claims 1 to 8, wherein the measurement in the second period is started based on the measurement operation of (1). 10. A flow path shutoff means for shutting off the gas flow path when the leak judgment means judges that gas is leaking. The gas meter according to any one of claims 1 to 9. 11. A communication terminal means for mutually communicating between the leak determining means and an external monitoring center, wherein the leak determining means determines that a gas leak has occurred. The gas meter according to any one of claims 1 to 10, wherein warning information is transmitted to the monitoring center via the communication terminal means. 12. The gas meter according to claim 1, wherein the length of the first period is changeable. 13. The gas meter according to claim 1, wherein the length of the second period can be changed. 14. A learning flow rate of fuel gas consumed by one or more gas combustion devices is measured per unit time during a first period, and the learning flow rate is measured when the first period elapses. Setting the comparison flow rate on the basis of, after the elapse of the first period, measuring the target flow rate of the fuel gas consumed by one or more gas combustion devices per unit time, the target flow rate It is determined whether or not the target flow rate is smaller than the comparative flow rate when the state where the target flow rate is smaller than the comparative flow rate continues for a second period. A gas leak detection method characterized by making a judgment. 15. The method according to claim 14, wherein the comparison flow rate is set to be equal to a minimum flow rate among the learning flow rates. 16. Based on an ignition flow rate range set based on an ignition flow rate of the gas-fired device, after the first period has elapsed, when the target flow rate is within the ignition flow rate range, gas leakage may occur. 15. The method according to claim 14, wherein it is determined that no gas leak has occurred. 17. The gas leak detection method according to claim 16, wherein the comparison flow rate is set to be equal to a minimum flow rate of the learning flow rate outside the range of the ignition flow rate. 18. The gas leak detection method according to claim 16, wherein the ignition flow range is set from outside. 19. Based on an ignition flow setting range for setting the ignition flow range stored before the first period, when the first period elapses,
18. When the part of the learning flow is within the ignition flow setting range, the ignition flow range is set based on the learning flow at this time. Gas leak detection method. 20. The gas according to claim 14, wherein the learning flow rate and the target flow rate are measured for each and all of the one or more gas-fired devices. Leak detection method. 21. The gas leakage detection method according to claim 14, wherein at least the comparative flow rate is stored. 22. The method according to claim 14, wherein the measurement of the second period is started at a time when it is determined that the target flow rate is smaller than the comparison flow rate. Gas leak detection method. 23. The gas leak detection device according to claim 14, wherein the gas flow path is shut off when it is determined that a gas leak has occurred. Method. 24. The apparatus according to claim 14, wherein when it is determined that gas leakage has occurred, warning information is transmitted to an external monitoring center. Gas leak detection method. 25. The gas leak detection method according to claim 14, wherein the length of the first period is changeable. 26. The gas leakage detection method according to claim 14, wherein the length of the second period is changeable.