JPH11287692A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas meter which prevents a gas flow passage from being mistakenly shut off even if gas combustion equipment is used continuously for a long time and this is regarded as an abnormal condition such as the leakage of gas. SOLUTION: A gas meter has a weighing mechanism part 100 which outputs a flow signal proportional to gas flow, a microphone 110 which detects the sound of gas combustion in gas equipment, a shutoff valve 140 which can shut off a gas flow passage in the gas meter, and a control part 160 for controlling the entire gas meter. When the gas flow is not smaller than a predetermined value and the sound of gas combustion is detected by a gas combustion sound detecting part 164, then the valve opening/closing control part 161 of the control part 160 immediately drives the shutoff valve 140 to shut off the gas flow passage. When the gas flow rate is less than the predetermined value, the corresponding time over which the gas meter is continuously usable is acquired not by detecting the sound of gas combustion but by consulting a table for continuously usable times. The gas flow passage is shut off when the gas flow rate is within a certain range over the time during which the gas meter is usable continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow path for ensuring safety by judging an abnormality when the flow rate of gas flowing through the flow path is substantially constant for a predetermined period of time and shutting off the gas flow path. The present invention relates to a gas meter having a shutoff valve, and more particularly to a gas meter having a means for preventing an erroneous shutoff operation of the flow path shutoff valve.

[0002]

2. Description of the Related Art In recent years, gas meters using a flow meter such as a membrane type flow meter or a fluidic flow meter have been put into practical use. 2. Description of the Related Art There is known a gas meter equipped with a microcomputer having a safety function of determining that an abnormality has occurred when the temperature is constant and shutting off a gas flow path. here,
“The gas flow rate is substantially constant” means that the change amount of the gas flow rate passing through the gas meter does not exceed, for example, 3%, and the microcomputer determines that the state within this range is a predetermined time (hereinafter referred to as “the gas flow rate”). , Continuous usable time), the safety valve is closed and the flow path is shut off, assuming that an abnormality such as gas leakage has occurred. On the other hand, when the gas flow rate exceeds the above range or when the gas flow rate becomes 0, the microcomputer resets the built-in monitoring timer and starts counting up the continuous usable time again from that point. It has become.

According to this type of gas meter, it is possible to detect an abnormality such as gas leakage in various gas combustion devices and pipes connected to the gas meter, thereby improving safety.

[0004] Conventionally, gas combustion control of gas appliances is performed by turning on and off the combustion itself in many cases. For this reason, if the combustion state of any gas equipment connected downstream of the gas meter changes,
The gas flow rate detected by the gas meter greatly exceeds the above range. At this point, the monitoring timer of the microcomputer is reset almost without exception. Therefore, there is almost no possibility of an erroneous shutoff operation in which the gas flow rate is determined to be within the above range and the safety valve is shut off even though the gas appliance is actually used.

[0005]

However, recently,
For example, as in the case of an air-conditioning gas appliance such as a hot-water circulation type floor heating system or a gas heat pump (GHP), a gas that does not perform the on / off control as described above but proportionally controls a gas combustion amount according to a required heat amount. Equipment is increasing. In this type of gas equipment, gas combustion often continues for a long time, and the gas usage does not fluctuate as much as the conventional on-off control type gas equipment. There is a possibility of being shut off accidentally as an abnormality such as gas leakage. In addition, the hot water circulation type floor heating system means that a gas is burned by a heat source device such as a gas central heating (GCH) boiler to produce hot water, and the hot water is circulated to a floor heating panel laid on the floor to thereby make the room indoors. Is a heating system.

As described above, in the conventional gas meter, when the proportional control type gas equipment is used for a long time, the continuous use time has been exceeded even though no abnormality such as gas leakage has occurred. There is a possibility that the gas flow path may be shut off upon judgment, which is inconvenient for the user.

The present invention has been made in view of such a problem, and an object of the present invention is to prevent a gas flow path from being erroneously shut off even when a proportional combustion type gas combustion apparatus is used continuously for a long time. It is to provide a gas meter.

[0008]

According to a first aspect of the present invention, there is provided a gas meter, comprising: a flow rate detecting means for detecting a flow rate of a gas flowing through a gas flow path; and a gas combustion device connected downstream of the gas flow path. A combustion sound detecting means for detecting a combustion sound accompanying the gas, and a flow path for shutting off the gas flow path when the gas flow rate is detected by the flow rate detecting means and the gas combustion sound of the gas combustion equipment is not detected by the combustion sound detecting means. Blocking means.

In this gas meter, when the gas flow rate is detected and the gas combustion noise of the gas combustion equipment connected downstream of the gas flow path is not detected, the gas flow path is shut off.

According to a second aspect of the present invention, there is provided a gas meter for detecting a flow rate of a gas flowing through a gas flow path, and detecting a combustion noise associated with gas combustion in a gas combustion device connected downstream of the gas flow path. A continuously usable time table in which the combustion sound detecting means to be used, the gas flow rate and the continuous usable time indicating the time during which the gas can be used continuously, and the gas flow rate detected by the flow rate detecting means are predetermined. When the value is equal to or more than the value, the gas flow path is shut off on condition that the gas combustion noise of the gas combustion device is not detected by the combustion noise detection means, and when the detected gas flow rate is less than the predetermined value,
The continuous flow time corresponding to the gas flow rate is obtained by referring to the continuous flow time table, and the gas flow path is provided on the condition that the change amount of the gas flow rate is within a predetermined range over the obtained continuous flow time. And a flow path blocking means for blocking the flow path.

In this gas meter, when the gas flow rate is equal to or more than a predetermined value, the gas flow path is shut off on the condition that the gas combustion noise of the gas combustion equipment is not detected. On the other hand, when the gas flow rate is less than the predetermined value, the continuous usable time table corresponding to the gas flow rate is obtained by referring to the continuous usable time table, and the change amount of the gas flow rate is set to the predetermined value over the continuous usable time. The gas flow path is shut off provided that it is within the range.

[0012]

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. In the present embodiment, a gas meter configured by combining a metering mechanism using a flow sensor and a metering mechanism using a fluidic element will be described.

As shown in FIG. 1, the gas meter according to the present embodiment has a piezoelectric film sensor 101 for detecting fluidic oscillation (described later) of a fluidic element which is in charge of detecting a flow rate in a large flow rate range, and a low flow rate sensor. A metering mechanism unit 100 having a flow sensor 102 for detecting a flow rate in an area, and a microphone 110 for detecting gas combustion noise of a gas appliance (not shown) connected downstream of the gas meter.
A display 120 for displaying the integrated flow rate, a shutoff valve 140 for shutting off a gas flow path (not shown in this drawing) in the gas meter as required, and a shutoff valve 14
There is provided a valve drive unit 150 for driving 0 and a control unit 160 for controlling the entire gas meter.

The control section 160 includes a valve opening / closing control section 161 connected to an input end of the valve driving section 150 and a weighing mechanism section 100.
162 connected to the piezoelectric film sensor 101 and the flow sensor 102, an integrator 163 connected to the output end of the flow calculator 162, and a gas combustion noise connected to the valve opening / closing controller 161 and the microphone 110. And a detection unit 164.

The valve opening / closing controller 161 includes a flow rate calculator 162
Is determined based on the flow rate value 166 from the fuel gas and the presence / absence of the combustion noise detection signal 167 from the gas combustion noise detector 164. As a result, when it is determined that the flow path should be The drive signal 165 is output to the valve drive unit 150 to close the shutoff valve 140. Flow calculator 162
Is configured to binarize flow signals from the piezoelectric film sensor 101 and the flow sensor 102 of the weighing mechanism unit 100, calculate a flow value 166 based on one or both of these signals, and output the calculated value. . The accumulator 163 is
The flow rate value 166 from the flow rate calculation unit 162 is integrated and output to the display 120.

When the sound signal output from the microphone 110 is in a predetermined frequency band and the signal level is equal to or higher than a predetermined level,
A combustion noise detection signal 167 is output. Generally, the frequency band of the combustion noise of a gas burner in a gas appliance is limited to a predetermined range centered on a few kHz band.
Therefore, the frequency band and the output level of the microphone 110 obtained with the gas combustion are checked by an experiment in advance, and the predetermined frequency band and the signal level are appropriately set based on the result. In this case, the gas combustion sound detection unit 164 can detect whether or not the gas appliance connected to the downstream pipe of the gas meter is in a combustion state. There are various other types of sound that can be transmitted through gas pipes.However, since such sound sources are far away, the signal level in the high frequency band is sufficiently attenuated, and Only the components arrive. Therefore, by limiting the frequency band to the predetermined range as described above and providing a threshold for the signal level, it is possible to eliminate the influence of noise.

The control unit 160 is constituted by using, for example, a microcomputer, and a ROM (Read Only Me
mory) or the like by executing a program stored therein. Here, the weighing mechanism 10
0 and the flow rate calculator 162 correspond to “flow rate detector” in the present invention, the microphone 110 and the gas combustion noise detector 164 correspond to “combustion noise detector” in the present invention, and the shutoff valve 140 and the valve driver 150 The valve opening / closing control section 161 corresponds to the “flow path blocking unit” in the present invention.

The display 120 is, for example, a liquid crystal display (LC).
D), and is configured to display a flow rate integrated value or the like output from the control unit 160. As will be described later, the microphone 110 is configured as an explosion-proof type disposed in the flow path on the gas outlet side of the measuring mechanism unit 100, and can detect a minute sound pressure fluctuation of, for example, 1 μH ₂ O. I have.

FIG. 2 shows a schematic configuration of the valve opening / closing control section 161 in FIG. As shown in this figure, the valve opening / closing control unit 161 controls the flow rate value 1 from the flow rate calculation unit 162.
A determination unit 161a to which the combustion noise detection signal 167 from the gas combustion noise detection unit 66 and the gas combustion noise detection unit 164 are input;
Continuous use time table 161b connected to 61c
And a timer 161c.

The determining unit 161a monitors the value of the flow rate value 166 and the presence or absence of the input of the combustion noise detection signal 167, and determines that there is a possibility of gas leakage if a predetermined condition described later is satisfied. The drive signal 165 is supplied to the valve drive unit 150 to drive the shutoff valve 140 to shut off the gas flow path.

The continuous usable time table 161b is, for example, as shown in FIG. 3, in which the continuous usable time is set in association with each range of the individual flow rate. It is being referred to. Here, the individual flow rate is defined as a value obtained by integrating the flow rate value 166 from the flow rate calculation unit 162 for a fixed time τ (for example, 30 seconds) at a time exceeding a certain range (for example, 3%). Is the amount of change in the flow rate per unit time obtained by calculation from the difference between the previous integrated value and the current integrated value. For example, in the example shown in FIG.
The quantity shown in Q3 corresponds to this. Note that FIG. 4 shows the average flow rate per unit time based on the integrated flow rate value for each fixed time τ and represents the average flow rate per time τ, and does not represent the real time change of the flow rate. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the average flow rate for each time τ.

In FIG. 3, the continuous usable time is the time during which continuous gas use is recognized, and the length thereof is set to a different value according to the magnitude of the individual flow rate. More specifically, when the gas is continuously used so as not to exceed a predetermined flow rate fluctuation range (for example, 3% or less), the flow path is shut off when the corresponding individual flow rate in FIG. 3 is reached. Is the continuous usable time.
In the example shown in FIG. 3, the range of the individual flow rate is divided into three with the upper limit being 1,000 liters / hour.
It does not specify a range exceeding 1,000 liters / hour. When the individual flow rate exceeds 1,000 liters / hour, the combustion sound detection signal 167 is used instead of the continuous usable time table 161b as described later.
This is because the control of shutting off the gas flow path is performed depending on the presence or absence of the gas flow path.
Here, the continuous usable time table 161b corresponds to the “continuous usable time table” in the present invention.

The timer 161c is for measuring the elapsed time (gas use time) starting from the time of the change when a certain individual flow rate is changed to another individual flow rate. Is reset by the start signal, and the timer operation is started.

FIG. 5 shows a sectional structure of the weighing mechanism section 100 shown in FIG. The metering mechanism 100 includes an inlet 11 for receiving gas and an outlet 12 for discharging gas.
And a main body 10 having: A partition 13 is provided in the main body 10, a first gas channel 14 is formed between the partition 13 and the inlet 11, and a second gas channel 15 is formed between the partition 13 and the outlet 12. Are formed. Partition 13
Is provided with an opening 16, and the above-described shutoff valve 140 (FIG. 1) is provided in the first gas flow path 14 so as to close the opening 16. A valve driving unit 150 (FIG. 1) made of a solenoid or the like is fixed to the outside of the main body 10,
The plunger 19 of the valve driving section 150 penetrates the side wall of the main body 10 and is connected to the shutoff valve 140. A spring 20 is provided around the plunger 19 between the shutoff valve 140 and the main body 10, and the spring 20 urges the shutoff valve 140 toward the opening 16. During normal use, the solenoid of the valve drive unit 150 is kept energized, and the shutoff valve 140 is separated from the opening 16.

In the second gas passage 15, there is provided a nozzle 21 for passing a gas received from the inlet 11 to generate a jet. A rectifying member 22 for adjusting the flow of gas is provided upstream of the nozzle 21. Downstream of the nozzle 21, a pair of side walls 23 and 24 that form an enlarged flow path are provided. This side wall 2
A predetermined interval is left between 3, 24, and the first
A target 25 and a second target 26 are provided on the downstream side, respectively. In addition, outside the side walls 23 and 24,
A return guide 2 that forms a pair of feedback channels 27 and 28 for returning the gas that has passed through the nozzle 21 to the ejection port side of the nozzle 21 along the outer peripheral portions of the side walls 23 and 24.
9 are provided. Also, the feedback channel 27,
28, a pair of discharge paths 3 is provided between the outlet portion 12 and the outlet portion 12 by the back surface of the return guide 29 and the main body 10.
1, 32 are formed. In the vicinity of the ejection port of the nozzle 21, pressure guiding holes 33 and 34 are provided to communicate with a piezoelectric film sensor for detecting a change in the direction of flow of the gas passing through the nozzle 21.

The flow sensor 1 is provided in the passage of the nozzle 21.
02 is provided. The flow sensor 102 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. The microphone 110 (FIG. 1) described above is provided on the inner surface of the gas flow passage near the outlet 12.

FIG. 6 is an enlarged cross-sectional view of the main body 10 including the pressure guiding holes 33 and 34 in FIG. As shown in this figure, a piezoelectric film sensor 101 is provided outside the bottom of the main body 10. Further, one ends of pressure guiding tubes 51 and 52 are connected to the pressure guiding holes 33 and 34, respectively. The other end of each of the pressure guiding tubes 51 and 52 is connected to each pressure inlet of the piezoelectric film sensor 101. Then, by the piezoelectric film sensor 101, the pressure guiding holes 33 and the pressure guiding holes 3 are formed.
4, the fluid pressure oscillation is detected based on the change in the pressure difference. In addition,
The pressure guiding tubes 51 and 52 and the piezoelectric film sensor 101 are
0 is covered by a case 55 fixed to the outside of the bottom.

Next, the operation of the gas meter configured as described above will be described.

First, the operation of the gas meter for measuring and displaying the flow rate will be described. In FIG. 5, the weighing mechanism 1
The gas received from the inlet 11 of the first nozzle 00 passes through the first gas flow path 14, the opening 16, the second gas flow path 15, and the rectifying member 22 in this order, and enters the nozzle 21. The gas that has passed through the nozzle 21 is jetted from the jet port as a jet. The gas ejected from the ejection port flows along one side wall due to the Coanda effect. Here, it is assumed that the flow first flows along the side wall 23. The gas flowing along the side wall 23 is further returned to the ejection port side of the nozzle 21 through the feedback channel 27 and is discharged from the outlet section 12 through the discharge path 31. At this time, the direction of the gas ejected from the nozzle 21 is changed by the gas flowing through the feedback flow path 27, and the gas flows along the other side wall 24 this time. This gas is further returned to the ejection port side of the nozzle 21 through the feedback channel 28 and discharged from the outlet section 12 through the discharge channel 32. Then, the direction of the gas ejected from the nozzle 21 is changed by the gas flowing through the feedback channel 28, and the side wall 2
3. Flow along the feedback flow path 27. By repeating the above operation, the gas that has passed through the nozzle 21 performs fluidic oscillation that alternately flows through the pair of feedback channels 27 and 28. The frequency and period of this fluid oscillation have a correspondence with the flow rate,
Detected by the piezoelectric film sensor 101 (FIG. 6) and output as a flow signal, the flow calculation unit 162 of the control unit 160
(FIG. 1).

On the other hand, the flow sensor 102 generates a temperature difference between two temperature sensors (not shown) according to the flow rate of gas flowing through the heating section (not shown) when a heating section (not shown) is heated with a constant current or constant power. Is output as a flow rate signal and input to the flow rate calculation unit 162.

In FIG. 1, a flow rate calculation unit 162 uses a flow rate signal from the piezoelectric film sensor 101 when the flow rate is in a large flow rate range suitable for measurement by a fluidic element, and the flow rate is suitable for measurement by the flow sensor 102. When the flow rate is in the small flow rate range, the flow rate is calculated using the flow rate signal from the flow sensor 102. Specifically, when using the piezoelectric film sensor 101, the flow rate calculation unit 162
A pulse is generated based on the flow rate signal from the controller, the number of pulses per unit time is counted, a frequency of the fluidic oscillation is obtained, and this frequency is converted into a flow rate. On the other hand, when the flow sensor 102 is used, the number of pulses per unit time of the flow signal from the flow sensor 102 is counted to determine the flow rate. When the flow rate is in a region where the large flow rate area and the small flow rate area intersect, the flow rate calculation unit 162 may calculate the flow rate from one of the outputs,
The flow rate may be obtained by an operation (for example, taking an average value) using both outputs. Or Japanese Unexamined Patent Publication
As described in JP-96817-A, the piezoelectric film sensor 1
Flow sensor 1 based on the measured value from the output from
02 may be calibrated.

The flow value 166 obtained by the flow calculating section 162 is sent to the integrating section 163 and also to the valve opening / closing control section 161. The integrating section 163 integrates the flow value 166 to obtain a flow integrated value, and displays the integrated value on the display 12.
Send to 0 for display. On the other hand, the valve opening / closing control unit 161
The value of the input flow value 166 is checked, and the presence or absence of the combustion sound detection signal 167 from the gas combustion sound detection unit 164 is checked. Is determined.

Next, with reference to FIG. 7, the operation of the gas meter for shutting off the flow path will be described.

FIG. 7 mainly shows the operation of the determination section 161a (FIG. 2) in the valve opening / closing control section 161. The determination unit 161a of the valve opening / closing control unit 161 includes a flow rate calculation unit 16
The flow rate value 166 from Step 2 is constantly monitored to check the gas usage state (Step S101). As a result, when the gas is used (Step S101; Y), the individual flow rate is calculated (Step S102). As described with reference to FIG. 4, the calculation of the individual flow rate is performed when the integrated value of the flow rate value 166 from the flow rate calculation unit 162 for each fixed time τ has changed beyond a certain range (here, 3%). This is performed by calculating the change in the average flow rate per unit time from the difference between the integrated value of the above and the current integrated value. For example, when the use of gas is started, ΔQ1 in FIG. 4 is the individual flow rate.

Next, the determination unit 161a determines in step S10
It is checked whether or not the individual flow rate obtained in step 1 is equal to or larger than a predetermined value Q (step S103). In the present embodiment, the predetermined value Q is, for example, 1 m ³ / hour, that is, a value of 1000 liters / hour which is the upper limit in the continuous usable time table 161b shown in FIG.

When the obtained individual flow rate is equal to or greater than the predetermined value Q (step S103; Y), the determination unit 161a
Is the combustion noise detection signal 16 from the gas combustion noise detection unit 164.
7 is checked (step S104). As a result, when the combustion sound detection signal 167 is not input (step S104; N), an abnormality such as gas leakage occurs because a relatively large gas flow rate exists despite not being in the gas combustion state. Then, the shutoff valve 140 is driven by outputting the valve drive signal 165 to the valve drive unit 150 to shut off the gas flow path (step S105). On the other hand, when the individual flow rate is equal to or more than the predetermined value Q (step S103; Y) and the combustion sound detection signal 167 is input from the gas combustion sound detection unit 164 (step S104; Y), Judgment unit 161a
Determines that the individual flow rate is due to gas combustion in the gas appliance, and returns to step S101 without interrupting the gas flow path.

On the other hand, when the obtained individual flow rate is less than the predetermined value Q (step S103; N), the judgment unit 1
61a is a continuous usable time table 161b.
With reference to FIG. 3, a continuous usable time T corresponding to the individual flow rate is obtained (step S106). And
The determination unit 161a sends a start signal to the timer 161c, resets the timer 161c, and starts the time counting operation (Step S107).

Thereafter, the determination unit 161a monitors the flow rate value 166 from the flow rate calculation unit 162 and the time count value from the timer 161c (steps S108 and S10).
9). Then, when the state where the integrated value of the flow rate value 166 for each fixed time τ is within a certain range (here, 3%) continues over the continuous usable time T (step S10).
8; N, step S109; Y), the determination unit 161a
It is determined that the individual flow rate is not due to the use of gas equipment but to the occurrence of an abnormality such as gas leakage, and the valve drive unit 150
By outputting the valve drive signal 165 to the shut-off valve 140
Is driven to shut off the gas flow path (step S105).
On the other hand, when the integrated value of the flow rate value 166 for each predetermined time τ exceeds the above-mentioned predetermined range (Step S108; Y), the process returns to Step S102, calculates the individual flow rate again, and performs the processing of Step S103 and subsequent steps.

For example, in FIG. 4, if the individual flow rate ΔQ1 at the beginning t1 when the gas is started is, for example, 800 liters / hour, this is equal to the predetermined value Q (= 1).
m ³ / hour), the continuous usable time T is set to 360 minutes by referring to the continuous usable time table 161b. Then, the timer 161c is reset to start the time counting operation, and the time-up of the continuous usable time of 360 minutes is monitored. If the flow rate subsequently changes and the individual flow rate ΔQ2 at time t2 is, for example, 400 liters / hour, the continuous usable time T is 7
At the same time, the timer is set to 20 minutes, the timer 161c is reset, and the timekeeping operation is restarted, and the continuous usable time of 720 minutes is monitored. In these cases, when the continuous use time T elapses, the shutoff valve 140 shuts off the gas flow path. On the other hand, the flow rate further changes after the continuous usable time T has not elapsed,
Assuming that the individual flow rate ΔQ3 at time t3 is, for example, 1600 liters / hour, this value is equal to the predetermined value Q
(= 1 m ³ / hour), the continuous usable time table 161 b is not referred to this time, and the presence or absence of the combustion sound detection signal 167 from the gas combustion sound detection unit 164, that is, the gas combustion sound of the gas appliance Is checked. When the gas combustion noise is not detected, the shutoff valve 140 shuts off the gas flow path.

As described above, according to the gas meter of the present embodiment, the individual flow rate as the flow rate change amount is equal to the predetermined value Q.
As described above, when the gas combustion noise is not detected, the gas flow path is immediately shut off, so only when it is recognized that the gas flow rate is not due to the normal use of the gas equipment, the gas flow is stopped. The flow path can be blocked. That is, even when using gas equipment that may perform proportional control of the combustion amount within a certain range (within 3%), such as a hot water circulation floor heating system or a gas heat pump, the gas flow rate is set to a predetermined value. If Q or more,
It can be distinguished whether it is due to gas combustion or gas leakage. Therefore,
When the proportional control type gas device is used for a long time, the gas flow path can be prevented from being erroneously shut off.

On the other hand, when the individual flow rate is less than the predetermined value Q,
Instead of depending on the presence or absence of the gas combustion noise, a corresponding continuous usable time T is set by referring to the continuous usable time table 161b, and it is detected that the gas flow rate was within a certain range over the continuous usable time T. The gas flow path is shut off when the gas is fired. When an abnormality such as occurs, the gas flow path can be reliably shut off.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications are possible. For example, in the above embodiment, the combustion noise is detected by the microphone. However, the present invention is not limited to this, and any other device may be used as long as it can detect the vibration sound accompanying the combustion. Can be used.

Further, in each of the above-described embodiments, the conditions for shutting off the gas flow path are different depending on whether the individual flow rate is equal to or more than the predetermined value Q or less than the predetermined value Q. If the gas combustion noise is not detected when the flow rate is detected, the gas combustion noise may be cut off immediately. In this case, a more sensitive microphone is used so that even a minute gas combustion noise can be detected,
The microphone may be arranged as close to the burner of the gas appliance as possible.

In the above embodiment, the piezoelectric film sensor 1 for detecting the fluidic oscillation of the fluidic element is used.
Although the gas meter using both the flow signal obtained from the flow sensor 01 and the flow signal obtained from the flow sensor 102 has been described, the present invention is not limited to this.
The present invention can be applied to a device using only a fluidic element or a device using only the flow sensor 102. further,
The present invention is also applicable to a gas meter using another type of flow meter such as a membrane flow meter.

[0046]

As described above, according to the gas meter of the first aspect, when the gas flow rate is detected,
Since the gas flow path is cut off on condition that the gas combustion noise of the gas combustion equipment is not detected, the gas flow path is cut off when there is a gas flow rate even though the gas equipment is not in the combustion state. be able to. Therefore,
For example, even when the combustion amount is controlled within a range that is considered to be almost constant in a proportional control type gas appliance, it is possible to discriminate whether the detected gas flow rate is due to gas combustion or gas leakage. It is possible. Therefore, there is an effect that it is possible to solve the problem that the gas flow path is erroneously shut off when the proportional control type gas device is used for a long time as in the related art.

According to the gas meter of the present invention, when the gas flow rate is equal to or more than the predetermined value, the gas flow path is shut off on condition that the gas combustion noise of the gas combustion equipment is not detected. Therefore, it is possible to prevent the gas flow path from being erroneously shut off when a gas appliance such as a proportional control system with a small change in the amount of combustion is used for a long time at a flow rate equal to or higher than a predetermined value. On the other hand, when the gas flow rate is less than the predetermined value, the continuous use time corresponding to the gas flow rate is obtained by referring to the continuous use time table, and the change amount of the gas flow rate is within a predetermined range over the continuous use time. Since the gas flow path is cut off on condition that the gas flow rate is below the predetermined value, use a gas appliance such as a small gas stove where it is difficult to detect the combustion noise because the gas combustion amount is smaller than a predetermined value. In this case, there is an effect that the gas flow path can be reliably shut off in response to the occurrence of an abnormality such as a gas leak.

[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 block diagram illustrating a schematic configuration of a valve opening / closing control unit of the gas meter illustrated in FIG.

FIG. 3 is a diagram illustrating an example of a continuously usable time table in a valve opening / closing control section illustrated in FIG. 2;

FIG. 4 is a timing chart for explaining the operation of the gas meter.

FIG. 5 is a cross-sectional view illustrating a main structure of a weighing mechanism illustrated in FIG.

FIG. 6 is an enlarged cross-sectional view illustrating a main structure of a weighing mechanism illustrated in FIG.

FIG. 7 is a flowchart for explaining the operation of the gas meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 100 ... Measurement mechanism part 101 ... Piezoelectric film sensor 102 ... Flow sensor 110 ... Microphone 140 ... Shutoff valve 150 ... Valve drive part 160 ... Control part 161 ... Valve opening / closing control part 161a ... Determining part 161b ... Continuous use time table 161c ... Timer 162: flow rate calculation section 164: gas combustion noise detection section 166 ... flow rate value 167: combustion noise detection signal

Claims (2)

[Claims] 1. A flow rate detecting means for detecting a flow rate of a gas flowing through a gas flow path, and a combustion sound detecting means for detecting a combustion sound accompanying gas combustion in a gas combustion device connected downstream of the gas flow path. And a gas flow rate is detected by the flow rate detection means, and
A gas meter, comprising: a flow passage shutoff unit that shuts off a gas flow passage when a gas combustion sound of a gas combustion device is not detected by the combustion sound detection unit. 2. A flow rate detecting means for detecting a flow rate of a gas flowing through a gas flow path, and a combustion sound detecting means for detecting a combustion sound accompanying gas combustion in a gas combustion device connected downstream of the gas flow path. And a gas flow rate, and a continuous usable time table in which a continuous usable time representing a time during which the gas can be continuously used, and a gas flow rate detected by the flow rate detecting means is equal to or more than a predetermined value. The gas flow path is shut off on condition that the gas combustion noise of the gas combustion equipment is not detected by the combustion noise detection means, and when the detected gas flow rate is less than the predetermined value, the continuous The continuous usable time corresponding to the gas flow rate is obtained by referring to the usable time table, and the change amount of the gas flow rate must be within a predetermined range over the obtained continuous usable time. A gas meter comprising: a flow path blocking unit configured to block the gas flow path.