JP3534504B2 - Gas meter - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas meter having a function of confirming the opening / closing operation of a shutoff valve.

[0002]

2. Description of the Related Art Conventionally, a gas meter has been provided with a shutoff valve for shutting off gas when an abnormality occurs. The opening / closing operation of the shutoff valve is performed according to the instruction of the electronic circuit in the gas meter.However, when the electronic circuit instructs the opening / closing operation of the shutoff valve, the electronic circuit determines whether the opening / closing operation of the shutoff valve has been performed reliably. It is hoped that it can be confirmed. As a method of confirming the opening / closing operation of the shutoff valve, a method of flowing a high-frequency electric signal through the coil of the solenoid valve used as the shutoff valve and measuring the impedance of the coil (hereinafter referred to as the first method),
How to confirm using the back electromotive force of the coil (hereinafter, the second
Method. ) Etc.

[0003]

However, the first method requires an oscillator circuit for generating a high frequency,
There is a problem that the circuit scale becomes large. In addition, there is a problem in that the gas meter that uses a battery as a power source may run out of battery capacity because power for the oscillation circuit is required. Further, the second method requires a dedicated circuit for confirming the opening / closing operation of the shutoff valve, and has a problem that it can detect only when the shutoff valve erroneously shuts off. Also, when both the first method and the second method are used together, the scale of the dedicated circuit becomes large, and the electronic circuit board of the existing gas meter cannot be accommodated, and the gas meter may need to be redesigned. There is also a problem that

The present invention has been made in view of the above problems, and an object thereof is to make it possible to confirm the opening / closing operation of a shutoff valve with a simple structure and without requiring a large amount of electric power. It is to provide a gas meter.

[0005]

According to a first aspect of the present invention, there is provided a gas meter for measuring a flow rate of gas in a large flow rate range, a first flow path for guiding the gas to the flow rate measurement section, and a first flow path for guiding the gas to the flow rate measurement section. A first cutoff valve for opening and closing the first flow path, a second flow path for guiding the gas to the flow rate measuring unit, a second cutoff valve for opening and closing the second flow path, and a second flow path in the second flow path. A flow velocity sensor for measuring the flow rate of gas in a small flow rate region, a first shutoff valve is closed and a second shutoff valve is opened in the small flow rate region, and a first shutoff valve in the large flow rate region. And a second shutoff valve are opened, and shutoff valve drive means for closing both the first shutoff valve and the second shutoff valve when shutting off the gas, and the shutoff valve drive means are provided for the first and second shutoff valves. Multiple movements performed on the valve
A shutoff valve operation confirmation means for confirming whether or not the opening and closing operations of the first and second shutoff valves are surely performed based on a combination of the content of the operation command and the output of the flow velocity sensor. .

In the gas meter according to the first aspect of the present invention, the shutoff valve drive means closes the first shutoff valve and the second shutoff valve in the small flow rate region, and opens the second shutoff valve in the large flow rate region. Both the second shutoff valves are opened and both the first shutoff valve and the second shutoff valve are closed when shutting off the gas. This shut-off valve drive means has the first and second shut-offs.
The contents of multiple operation commands issued to the valve and the flow velocity sensor
First and second cutoff based on combination with output
The open / closed state of the valve is confirmed.

A gas meter according to a second aspect is the gas meter according to the first aspect, wherein the shut-off valve driving means has the first flow path.
Shuts off when opening and closing the first shutoff valve of
The valve operation confirmation means performs an operation finger performed on the first shutoff valve.
The combination of the content of the decree and the output of the flow velocity sensor of the second channel
The opening / closing operation of the first shutoff valve is reliably performed based on
Whether or not it is confirmed .

In the gas meter according to the second aspect , the first
There is a flow velocity sensor when the shutoff valve of the flow path of is closed.
Gas is led to the flow path of the
In this state, gas is introduced into the first flow path. like this
Operation command issued to the first shutoff valve using the characteristics
And the output of the flow velocity sensor of the second flow path
The open / closed state of the shutoff valve of the first flow path is confirmed.

The gas meter according to claim 3 is the same as claim 2.
In addition, the shutoff valve drive means is
When the opening / closing operation is performed for the second cutoff valve of the second flow path
Then, the shutoff valve operation confirmation means performs the operation for the second shutoff valve.
Between the contents of the operation command and the output of the flow velocity sensor of the second flow path
The opening / closing operation of the second shutoff valve is reliable based on the combination.
It is to confirm whether or not it was done in.

In the gas meter according to the third aspect , the abnormality is
At times, if all shutoff valves operate normally and shut off,
Gas does not flow in all flow paths, but blocks the second flow path.
If the shutoff valve does not work properly and is not shut off, the gas
A small amount flows through the second flow path. On the other hand, all shutoff valves are normal
If the gas returns to the inside of the second flow path,
Flow, but the shutoff valve of the second flow path does not operate normally
If not attributed, the gas does not flow through the second flow path.
Utilizing such a feature, the operation is performed for the second shutoff valve.
Between the contents of the operation command and the output of the flow velocity sensor of the second flow path
Open / closed state of the shutoff valve of the second flow path based on the combination
Is confirmed.

The gas meter according to claim 4 is the same as claim 3.
In the above gas meter, the shutoff valve drive means is the first shutoff
When the valve is opened or closed and the second shutoff
When the valve is closed, the output of the flow velocity sensor is
Check whether the opening / closing operation has been performed properly based on the
When the valve shutoff drive means performs the opening operation of the second shutoff valve
The opening operation can be performed based on the variation in the output of the flow velocity sensor.
Blocking characterized by confirming whether or not it was done reliably
It has a valve operation confirmation means.

In the gas meter according to the fourth aspect , the abnormality is
At times, if all shutoff valves operate normally and shut off,
Gas does not flow in all flow paths, but blocks the second flow path.
If the shutoff valve does not work properly and is not shut off, the gas
A certain value from the flow velocity sensor because it flows in a small amount in the second flow path.
Is output. On the other hand, all shut-off valves operate normally and
If returned, a small amount of gas will flow in the second flow path.
As a result, the flow velocity sensor will output a variable value.
If the shutoff valve in the flow path of does not operate normally and is not restored
Is the flow velocity because the gas hardly flows in the second flow path.
The values output from the sensor vary slightly. like this
Action finger performed on the second shut-off valve using
The combination of the content of the decree and the output of the flow velocity sensor of the second channel
The open / closed state of the shutoff valve of the second flow path is confirmed based on
Be done.

The gas meter according to claim 5 is the same as claim 1.
In the gas meter described in Ishi 4, the flow rate measuring unit is a nozzle
To generate fluidic oscillation due to the gas passing through the
This is the fluidic oscillation generator and this fluidic oscillation generator.
Detects fluidic oscillations generated by Narube
With a fluidic oscillation detection sensor
Of.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG . 1 is a sectional view showing the structure of a gas meter according to an embodiment of the present invention. As shown in this figure, the gas meter comprises a body 10 having an inlet 11 for receiving gas and an outlet 12 for discharging gas. A partition wall 13 is provided in the main body 10, and the entrance portion 11 is provided.
A channel 14 is provided from the partition wall 13 to the partition wall 13. A fluidic element 30 as a fluidic oscillation generator is provided in the main body 10, and the fluidic element 30 is provided.
A flow path 50 is provided from to the outlet 12. A fluidic channel 15 and a flow sensor channel 17 are provided in parallel between the partition wall 13 and the fluidic element 30. The fluidic channel 15 is
The cross-sectional area is larger than that of the flow sensor channel 17. The partition wall 13 is provided with an opening 16 communicating with the fluidic flow path 15 and an opening 18 communicating with the flow sensor flow path 17. A valve seat 16a is provided in the opening 16.
Is provided, and the opening 18 is provided with a valve seat 18a.

In the flow sensor flow path 17, a nozzle portion 19 near the outlet and a gas passing through the nozzle portion 19 are in substantially the same direction as the gas passing through the fluidic flow path 15 in the fluidic direction. A rectifying member 20 that regulates the flow of gas toward the element 30 is provided, and the nozzle portion 19 is provided.
A check valve 70 is provided upstream of the check valve 70. Nozzle part 19
A flow sensor 51 (not shown in FIG. 1) that detects the flow velocity of the gas passing through the nozzle portion 19 is provided therein.

The gas meter further includes a fluidic shutoff valve 21 for opening and closing the fluidic flow path 15 and a flow sensor shutoff valve 2 for opening and closing the flow sensor flow path 17.
2 and. Both the fluidic shutoff valve 21 and the flow sensor shutoff valve 22 can electrically perform an operation from an open state to a closed state and an operation from a closed state to an open state. Shutoff valve for fluidics 2
1 is a valve body 23 for opening and closing the opening 16 and a valve body 2 is one end.
3 is connected to the rod 24 and an actuator 25 fixed to the outside of the main body 10 and connected to the other end of the rod 24.
And have. The actuator 25 drives the valve element 23 via the rod 24 to open and close the opening 16. The flow sensor cutoff valve 22 includes a valve body 26 that opens and closes the opening 18, a rod 27 having one end connected to the valve body 26, and an actuator fixed to the outside of the main body 10 and connected to the other end of the rod 27. 28 and. The actuator 28 drives the valve body 26 via the rod 27 to open and close the opening 18.

The fluidic element 30 includes a nozzle 31.
And a pair of side walls 33, 34 provided on the downstream side of the nozzle 31 and forming an enlarged flow path. A target 35 is provided on the upstream side and a target 36 is provided on the downstream side with a predetermined space between the side walls 33 and 34. The nozzle 3 is provided outside the side walls 33 and 34.
A return guide 39 is provided which forms a pair of feedback flow paths 37, 38 for returning the gas passing through 1 to the ejection port side of the nozzle 31 along the outer peripheral portions of the side walls 33, 34. A pair of discharge passages 41 and 42 are formed between the outlets of the feedback flow passages 37 and 38 and the flow passage 50 by the back surface of the return guide 39 and the main body 10. In the vicinity of the ejection port of the nozzle 31, pressure guiding holes 43,
44 is provided, and communicates with the pressure guiding holes 43, 44 on the outer side of the bottom of the main body 10 via a pressure guiding path (not shown).
3, a piezoelectric film sensor 45 (not shown in FIG. 1) as a fluidic oscillation detection sensor for detecting a pressure difference between the pressure guiding hole 44 and the pressure guiding hole 44 is provided.

The gas passing through the fluidic flow path 15 or the flow sensor flow path 17 reaches the fluidic element 30. Here, the gas that has passed through the nozzle 31 is
It becomes a jet and is jetted from the jet outlet. The gas ejected from the ejection port flows along one side wall due to the Coanda effect. Here, it is assumed that the material flows first along the side wall 33. The gas flowing along the side wall 33 is further returned to the ejection port side of the nozzle 31 via the feedback flow path 37.
It is discharged to the flow path 50 via the discharge path 41. At this time, the gas ejected from the nozzle 31 is fed back into the feedback passage 3
The gas flowing through 7 changes its direction, and in turn, flows along the other side wall 34. This gas is
Further, it is returned to the ejection port side of the nozzle 31 via the feedback flow path 38, and is discharged to the flow path 50 via the discharge path 42. Then, the direction of the gas ejected from the nozzle 31 is changed by the gas flowing through the feedback flow path 38, and the side wall 33 and the feedback flow path 3 again.
It comes to flow along 7. By repeating the above operation, the gas passing through the nozzle 31 performs fluidic oscillation which alternately flows through the pair of feedback flow paths 37 and 38. The frequency and period of this fluidic oscillation have a correlation with the flow rate. The fluidic oscillation is detected by the piezoelectric film sensor 45.

Next, the check valve with reference to FIGS 70
The configuration of will be described. 2 is a cross-sectional view of the check valve 70,
3 is a sectional view taken along the line AA of FIG. 2, and FIG. 4 is a sectional view taken along the line BB of FIG. The vicinity of the nozzle portion 19 in FIG. 1 shows a cross section taken along the line CC of FIG. The check valve 70 includes a cylindrical case 210 whose both ends are closed, and a float 220 slidably accommodated in the case 210. In the case 210, a circular gas inlet portion 211 is formed at the bottom portion, and a vertically long gas outlet portion 212 is formed at a position below the side portion. Exit 2
12 is arranged on the opposite side of the flow sensor 51 with the float 220 interposed therebetween. A small hole 214 for guiding the pressure on the downstream side of the check valve 70 into the case 210 is provided in the upper part of the case 210. The case 210 is fixed in the flow sensor channel 17 by a case receiving plate 215 that holds the bottom of the case 210 and a case retainer 216 that holds the side of the case 210. As shown in FIGS. 2 and 4, the outlet portion 212 forms a gap 217 between the case receiving plate 215 and the case retainer 216 and a gap 218 between the outer peripheral portion of the case 210 and the wall of the flow sensor channel 17. Check valve 7 through
0 communicates with the downstream side.

The float 220 is formed in a cylindrical shape whose lower end surface is open and whose upper end surface is closed. When the float 220 is located at the bottom of the case 210, the side wall of the float 220 closes the outlet portion 212 and shuts off the upstream side and the downstream side of the check valve 70.
The float 220 rises in the case 210, and the float 2
When the lower end of 20 becomes higher than the lower end of the outlet portion 212, the outlet portion 212 is opened so that the upstream side and the downstream side of the check valve 70 are communicated with each other.

As shown in FIG . 2, the flow sensor 51 is arranged so as to face the passage in the nozzle portion 19.
Although not shown, the flow sensor 51 has a heat generating part and two temperature sensors arranged on the upstream side and the downstream side of the heat generating part, and keeps a constant temperature difference detected by the two temperature sensors. Therefore, it is possible to obtain the flow rate corresponding to the flow velocity from the power supplied to the heat generating section, or to heat the heat generating section with a constant current or constant power and obtain the flow rate from the temperature difference detected by the two temperature sensors. It has become. In the flow path between the nozzle portion 19 and the check valve 70, a strainer 23 made of a plate having a large number of holes formed therein.
0 is set.

[0023] Here, a description will be given of the operation of the check valve 70. When no gas is flowing, there is no pressure difference between the upstream side and the downstream side of the check valve 70. Therefore, as shown in FIG.
It is located at the bottom of the inside, and the outlet part 212 is completely closed, and the upstream side and the downstream side of the check valve 70 are shut off. On the other hand, when the gas starts to flow, a pressure difference occurs between the pressure on the upstream side of the check valve 70 introduced from the inlet portion 211 and the pressure on the downstream side of the check valve 70 introduced via the small holes 214. The float 220 is lifted by the buoyancy caused by the pressure difference, and rises in the case 210. As a result, the outlet portion 212 is opened by an amount corresponding to the pressure difference, and the gas passes through the check valve 70. Here, the gas is the check valve 7
By passing through 0, the load force by the float 220 is received, and the pressure fluctuation is absorbed. Check valve 7
The gas that has passed through 0 is strainer 230 and nozzle 1
9. The fluidic element 3 is passed through the rectifying member 20 in order.
Go to 0.

In the gas meter according to this embodiment, the flow sensor shutoff valve 22 is open except when there is an abnormality. Therefore, the shutoff valve 21 for fluidic
Is closed and the fluidic flow path 15 is closed,
The gas passes through the flow sensor flow path 17. On the other hand, when the fluidic shutoff valve 21 is opened and the fluidic flow passage 15 is opened, the flow sensor flow passage 17 is more likely to flow in the flow sensor flow passage 17 than the fluidic flow passage 15 due to pressure loss due to the check valve 70. The pressure loss increases, and the gas flow in the flow sensor flow path 17 stops.

FIG . 5 is a block diagram showing the circuit configuration of the gas meter according to this embodiment. As shown in this figure, the gas meter includes a flow sensor 51 and an output signal of the flow sensor 51, which is analog-digital (hereinafter referred to as A).
/ D. ) A / D converter 52 for converting, piezoelectric film sensor 45, analog amplifier 53 for amplifying the output signal of this piezoelectric film sensor 45, and waveform for shaping the output signal of this analog amplifier 53 to generate a pulse Shaping circuit 5
4, a flow rate calculation unit 55 that calculates a flow rate based on at least one of the output of the A / D converter 52 and the output of the waveform shaping circuit 54, and the flow rate calculated by the flow rate calculation unit 55 is integrated to obtain an integrated flow rate. And an integrating unit 56 for calculating
The display unit 57 that displays the integrated flow rate that has been integrated by the shutoff valve drive unit 58 that issues an opening / closing operation instruction to the fluidic shutoff valve 21 according to the flow rate calculated by the flow rate calculation unit 55.
And a content of the opening / closing operation instruction of the shut-off valve driving sections 58, 59, which outputs an opening / closing operation instruction to the flow sensor shut-off valve 22 according to the flow rate calculated by the flow rate calculation section 55, and A A valve operation confirming unit 6 for confirming whether or not the opening / closing operations of the shutoff valves 21 and 22 are surely performed based on the output of the / D converter 52 (hereinafter, also referred to as a flow sensor output).
0, and an abnormality is detected based on the flow rate calculated by the flow rate calculation unit 55, and when there is an abnormality, the shutoff valves 21 and 22 are shut off to shut off the gas, and a gas leakage inspection is performed when the gas returns. 61 and. Flow rate calculator 5
5, integrating unit 56, shutoff valve drive unit 58, shutoff valve drive unit 5
9, the valve operation confirmation unit 60 and the safety function unit 61 are configured by, for example, a microcomputer.

[0026] Here, an outline of operation of the gas meter according to the present embodiment. When the flow rate is in a small flow rate range below a predetermined flow rate (for example, 1000 liters / hour), the fluidic cutoff valve 21 is closed and the flow sensor cutoff valve 22 is opened, so that the flow rate exceeds the predetermined flow rate. When in the large flow rate region, the fluidic shutoff valve 21 is open and the flow sensor shutoff valve 22 is also open.
In the small flow rate region, the gas taken in from the inlet 11 passes through the flow sensor flow path 17 and the fluidic element 30.
Reach the exit point, pass through the fluidic element 30, and exit 12
More discharged. At this time, the flow sensor 51 detects the flow velocity of the gas passing through the nozzle portion 19 in the flow sensor flow path 17. Further, the check valve 70 absorbs the gas pressure fluctuation. The flow rate calculation unit 55 calculates the flow rate based on the output of the flow sensor in the small flow rate range.

On the other hand, in a large flow rate region, the gas taken in from the inlet portion 11 through only fluidic flow path 15, reaches the fluidic element 30, it passes through the fluidic element 30, discharged from the outlet portion 12 To be done. here,
Since the gas passes through the fluidic flow path 15 having a larger cross-sectional area than the flow sensor flow path 17, occurrence of gas supply failure at a large flow rate is prevented. The flow rate calculation unit 55
In the large flow rate region, the flow rate is calculated using the fluidic element 30, that is, based on the output of the piezoelectric film sensor 45 (output of the waveform shaping circuit 54). The flow sensor 5
1 and the output of the piezoelectric film sensor 45 are overlapped to provide a flow rate region in which the piezoelectric film sensor 4 is provided.
The flow rate calculated based on the output of the flow sensor 51 is used as a formal flow rate, and the flow rate calculated based on the output of the piezoelectric film sensor 45 is used to correct the flow rate calculated based on the output of the flow sensor 51. The official value may be an average value of the flow rate calculated based on the output of 45 and the flow rate calculated based on the output of the flow sensor 51.

The shutoff valve drive section 58 closes the fluidic shutoff valve 21 when the flow rate calculated by the flow rate calculation section 55 is in the small flow rate range, and when the flow rate is in the large flow rate range, it is for the fluidic control. The shutoff valve 21 is opened. The shutoff valve drive unit 59 keeps the flow sensor shutoff valve 22 open regardless of whether the flow rate calculated by the flow rate calculation unit 55 is in the small flow rate range or in the high flow rate range.

The safety function unit 61 activates the shut-off valve drive units 58 and 59 when the flow rate calculated by the flow rate calculation unit 55 is abnormally large, or when the flow rate exceeds a predetermined value for a predetermined time or more. By controlling the shutoff valves 21 and 22, the gas is shut off. Further, the safety function unit 61 controls the shutoff valve drive unit 59 to open the shutoff valve 22 for the flow sensor at the time of gas return, and then performs the gas leakage inspection based on the flow rate calculated by the flow rate calculation unit 55. And there is no flow,
If it is determined that there is no gas leakage, the operation proceeds to normal operation of the gas meter, and there is a flow rate, and if it is determined that there is gas leakage, the shutoff valve 22 is closed again to shut off gas.

Next, with reference to FIG. 6, the valve operation check unit 60
The operation of will be described in detail. As shown in FIG.
The shutoff valves 21 and 22 are opened / closed when the flow rate is changed from a large flow rate to a small flow rate, when the flow rate is changed from a small flow rate to a large flow rate, when the gas is shut off, and when the gas is restored.

When the flow rate is changed from a large flow rate to a small flow rate, the flow sensor cutoff valve 22 remains open, and the fluidic cutoff valve 21 is changed from the open state to the closed state. Here, when the fluidic shutoff valve 21 operates normally, the flow sensor output increases because the fluidic flow path 15 is closed, but the fluidic shutoff valve 2
When 1 does not operate normally (in the open state), the flow sensor output is small because the fluidic channel 15 is open.

[0032] Therefore, when the cutoff valve driving unit 58 has issued an instruction to close the fluidic cutoff valve 21, the valve operation check unit 60 checks the flow sensor output, the flow sensor output is the predetermined threshold TH1 or less In this case, it is determined that the fluidic shutoff valve 21 is open, and in other cases, it is determined that the fluidic shutoff valve 21 is closed.
When determining that the fluidic shutoff valve 21 is open, the valve operation confirmation unit 60 controls the shutoff valve drive unit 58 to issue an instruction to close the fluidic shutoff valve 21 again.

When the flow rate is changed from a small flow rate to a large flow rate, the flow sensor shut-off valve 22 remains open and the fluidic shut-off valve 21 is changed from the closed state to the open state. Here, when the fluidic shutoff valve 21 operates normally, the flow sensor output becomes small because the fluidic flow path 15 is open, but the fluidic shutoff valve 2
When 1 does not operate normally (in the closed state), the flow sensor output is large because the fluidic flow path 15 is closed.

[0034] Therefore, when the cutoff valve driving unit 58 has issued an instruction to open the fluidic cutoff valve 21, the valve operation check unit 60 checks the flow sensor output, the flow sensor output a prescribed threshold value TH1 When it exceeds, it is determined that the fluidic shutoff valve 21 is closed, and in other cases, it is determined that the fluidic shutoff valve 21 is open.
When determining that the fluidic shutoff valve 21 is closed, the valve operation confirmation unit 60 controls the shutoff valve drive unit 58 to issue an instruction to open the fluidic shutoff valve 21 again.

When shutting off the gas, shut off valve 2 for fluidic
1 and the shutoff valve 22 for the flow sensor are changed from the open state to the closed state. Here, the shutoff valve 22 for the flow sensor
Is normally operating, the flow sensor flow path 17 is closed and the flow sensor output is almost zero.
When the flow sensor cutoff valve 22 does not operate normally (in the open state), the flow sensor flow path 17 is open, and therefore the flow sensor output has a certain value.

[0036] Therefore, when the cutoff valve driving unit 59 has issued an instruction to close the flow sensor cutoff valve 22, the valve operation check unit 60 checks the flow sensor output, when the flow sensor output is other than zero (or flow If the sensor output exceeds a predetermined value close to zero), the flow sensor shutoff valve 22
Is determined to be open, and in other cases, the flow sensor cutoff valve 22 is determined to be closed. Valve operation confirmation unit 60
When determining that the flow sensor cutoff valve 22 is open, controls the cutoff valve drive unit 59 to issue an instruction to close the flow sensor cutoff valve 22 again.

When returning to gas, the shut-off valve 22 for the flow sensor
Is changed from the closed state to the open state. Immediately after the gas is returned, the safety function unit 61 performs a gas leak inspection, and if there is a flow rate, it is determined that there is a gas leak,
The gas is shut off again. Therefore, it is not possible to confirm the operation of the flow sensor shutoff valve 22 based on the magnitude of the flow sensor output. Therefore, in this embodiment, in order to confirm the operation of the flow sensor shutoff valve 22 in the state where there is no flow rate, the variation in the flow sensor output is used. That is, the shutoff valve 22 for the flow sensor when the gas returns
Is normally operated, the flow sensor flow path 17 is opened, so that the flow sensor output varies due to a slight change in the gas supply pressure, but the flow sensor cutoff valve 22 does not operate normally ( In the closed state), the flow sensor flow path 17 is closed, so that the variation in the flow sensor output becomes almost zero.

When the shutoff valve drive unit 59 gives an instruction to open the shutoff valve 22 for the flow sensor, the valve operation confirmation unit 60
Examines the flow sensor output, determines that the flow sensor shutoff valve 22 is closed when the variation in the flow sensor output is less than or equal to a predetermined threshold value TH2, and otherwise determines the flow sensor shutoff valve 22. Determine that is open. The variation of the flow sensor output is, for example, the difference between the maximum value and the minimum value of the flow sensor output within a predetermined time. When determining that the flow sensor cutoff valve 22 is closed, the valve operation confirmation unit 60 controls the cutoff valve drive unit 59 to issue an instruction to open the flow sensor cutoff valve 22 again.

[0039] According to the gas meter according to this embodiment as described above, for example, by a valve operation check unit 60 can be constituted by a microcomputer, the cutoff valve driving unit 58,5
Based on the content of the opening / closing operation instruction of 9 and the output of the flow sensor, it is confirmed whether or not the opening / closing operations of the shutoff valves 21 and 22 are surely performed, so that a dedicated circuit is not required,
There is no need to enlarge the electronic circuit board of the gas meter. Further, since no special electric power is required to confirm the opening / closing operation of the shutoff valves 21 and 22, it is possible to prevent the power consumption of the gas meter from increasing.

The present invention is not limited to the above-mentioned respective embodiments, and for example, the flow sensor is not limited to the one having the heat generating part and the two temperature sensors, but has, for example, one heat generating part. The flow velocity is calculated from the power supplied to the heat generating part necessary to keep the temperature (resistance) of the heat generating part constant,
It is also possible to heat the heat generating portion with a constant current or constant power and obtain the flow velocity from the temperature (resistance) of the heat generating portion.

Further , the flow rate measuring unit is a fluidic element 3
The flow rate is not limited to 0, and the flow rate may be measured by another method.

[0042]

As described above, according to the gas meter of the present invention, the flow rate measuring section for measuring the flow rate of the gas in the large flow rate range, and the first flow path for guiding the gas to the flow rate measuring section, A first cutoff valve that opens and closes the first flow path; a second flow path that guides the gas to the flow rate measurement unit; a second cutoff valve that opens and closes the second flow path; Of the flow rate sensor for measuring the gas flow rate in the small flow rate region, the first shut-off valve is closed and the second shut-off valve is opened in the small flow rate region, and the first flow rate sensor is opened in the large flow rate region. A shut-off valve driving means for opening both the first shut-off valve and the second shut-off valve and closing both the first shut-off valve and the second shut-off valve when shutting off the gas;
The shut-off valve driving means couples to the first and second shut-off valves.
Output and to content and flow rate sensor of the plurality of operation command went
A shut-off valve operation confirmation means for confirming whether or not the opening and closing operations of the first and second shut-off valves are reliably performed based on the combination of There is an effect that the opening / closing operation of the shutoff valve can be confirmed without requiring electric power.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a gas meter according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a specific configuration of the check valve in FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is a block diagram showing a circuit configuration of a gas meter according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram for explaining the operation of the gas meter according to the embodiment of the present invention.

[Explanation of symbols]

15 Fluidic channel 17 Flow sensor flow path 21 Shutoff valve for fluidics 22 Shut-off valve for flow sensor 30 Fluidic element 45 Piezoelectric film sensor 51 Flow sensor 58 Shut-off valve drive 59 Shut-off valve drive 60 valve operation confirmation part 61 Safety Function Department 70 Check valve

─────────────────────────────────────────────────── ───Continued from the front page (56) References JP-A-62-175619 (JP, A) JP-A-2-114123 (JP, A) JP-A-6-160158 (JP, A) Actual development Sho-61- 63085 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 1/00-9/02

Claims (5)

(57) [Claims] 1. A flow rate measuring section for measuring the flow rate of gas in a large flow rate range, a first flow path for guiding the gas to the flow rate measuring section, and a first cutoff for opening and closing the first flow path. A valve, a second flow path that guides gas to the flow rate measuring unit, a second shutoff valve that opens and closes the second flow path, and a second cutoff valve that is disposed in the second flow path and is used in a small flow rate range. The flow velocity sensor for measuring the flow rate of gas, the first shutoff valve is closed and the second shutoff valve is opened in the small flow rate range, and both the first shutoff valve and the second shutoff valve are opened in the large flow rate range. When opening and shutting off gas, the first shutoff valve and the second shutoff valve
Shut-off valve driving means for closing both shut-off valves, and the shut-off valve driving means for pairing the shut-off valve with the first and second shut-off valves.
The first and second shutoff valves based on the combination of the contents of the plurality of operation commands and the output of the flow velocity sensor.
A shutoff valve operation confirmation means for confirming whether or not the opening / closing operation of the gas meter has been reliably performed. 2. The shutoff valve operation confirmation means is the shutoff valve drive.
The moving means opens and closes the first cutoff valve of the first flow path.
Of the operation command issued to the first shutoff valve
Combination of contents and output of the flow velocity sensor of the second flow path
The opening / closing operation of the first shutoff valve is reliably performed based on
The gas according to claim 1, wherein it is confirmed whether or not
Smeter. 3. The shut-off valve operation confirmation means further comprises:
The shutoff valve drive means opens the second shutoff valve of the second flow path.
The action performed on the second shutoff valve when the closing operation was performed.
Of the contents of the operation command and the output of the flow velocity sensor of the second flow path
The opening / closing operation of the second shutoff valve is reliable based on the combination.
3. It is confirmed whether or not it has been performed in step 2.
The described gas meter. 4. The shutoff valve operation confirmation means includes the flow velocity sensor when the shutoff valve drive means performs an opening operation or a closing operation of a first shutoff valve and when a shutoff operation of a second shutoff valve is performed. Whether or not the opening / closing operation is surely performed based on the magnitude of the output of the second shut-off valve driving means performs the opening operation of the second shut-off valve based on the magnitude of the variation in the output of the flow velocity sensor. The gas meter according to claim 3, wherein it is confirmed whether or not the opening operation is reliably performed. 5. The fluid flow measuring unit includes a fluidic oscillation generation unit that generates a fluidic oscillation due to a gas that has passed through a nozzle, and a fluidic oscillation detection unit that detects the fluidic oscillation generated by the fluidic oscillation generation unit. of claim 1, characterized in that it comprises a sensor
The gas meter according to any one of 1 to 4 .