JP2002350213A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas meter capable of measuring a gas flow with high accuracy. SOLUTION: The gas meter is formed by a gas passage 21, ultrasonic transmitter/receivers 34, 35 for measuring the flow of gas flowing through the gas passage, and a control part for measuring the flow of gas according to output of the ultrasonic transmitter/receivers 34, 35. The gas flow can be measured with high accuracy according to transmission/receiving of ultrasonic waves by the ultrasonic transmitter/receivers 34, 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas meter for measuring a gas flow rate.

[0002]

2. Description of the Related Art Conventionally, as this type of flow rate measuring device, there is a membrane type gas meter provided with a measuring membrane disclosed in Japanese Patent Application Laid-Open No. H08-210893.

As shown in FIG. 18, this type of membrane gas meter has a pair of measuring chambers provided with an inlet 1 through which a gas to be measured flows in, an outlet 2 through which gas flows out, and a measuring membrane (not shown). (Not shown) and a weighing unit 3 for storing the weighing unit 3
And a display unit 4 for displaying the amount of gas that has passed through.

In such a configuration, the metering operation of the membrane gas meter is performed by reciprocating the metering membrane at a gas pressure in a pair of metering chambers having a fixed volume, and measuring the flow rate by the number of operations, as is well known in the art. Is what you do.

[0005]

However, in the prior art, the gas meter is provided for the detection of leakage, while the security function for detecting and notifying the leakage of gas from the gas pipe or gas appliance downstream of the gas meter is provided. The problem is that it is necessary to pass a gas amount of about the capacity of the measuring chamber, and it takes a longer time to detect a leak (for example, 1 hour for a measuring chamber volume of 3 liters) as the leak becomes smaller (for example, a flow rate of about 3 liters per hour). There is. Further, the larger the maximum flow rate of the gas meter (the number of the gas meters), the larger the volume of the measuring chamber. Therefore, there is a security problem that it takes much longer to detect a leak.

[0006]

According to the present invention, there is provided an ultrasonic transducer for measuring a flow rate of a gas flowing in a gas flow path, and an output from the ultrasonic transducer is provided. And a controller for measuring the flow rate of the gas based on the above.

According to the present invention, the gas flow rate can be measured by ultrasonic waves with the above-described configuration, and the flow rate measurement can be performed with high accuracy.

[0008]

DETAILED DESCRIPTION OF THE INVENTION A gas meter according to a first aspect of the present invention includes a gas flow path, an ultrasonic transducer provided for measuring a flow rate of a gas flowing in the gas flow path, and an ultrasonic transducer. And a controller for measuring the gas flow rate based on the output from the wave device, and measures the gas flow rate by transmitting and receiving ultrasonic waves by the ultrasonic wave transmitter / receiver.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a front view and a side view showing an installation state in which the gas meter of the present invention is connected by piping.
In the figure, an inlet-side base 6 provided on the upper left side of the gas meter main body 5 and an outlet-side base 7 provided on the upper right side are connected to the inflow side pipe 8 and the outflow side pipe 9. Reference numeral 10 denotes a main body cover provided on the front surface of the gas meter main body 5, reference numeral 11 denotes a battery storage cover provided below the front surface of the gas meter main body 5, and reference numeral 12 denotes a bottom cover provided below the gas meter main body 5. 13 is a display window for switching and displaying the display such as instantaneous flow rate value, integrated flow rate value, abnormality notification, etc., and 14 is a return button for resetting the gas flow path to an available state after closing the gas flow path in case of abnormality. The display window 13 and the return button 14 are arranged on the main body cover 10.

Next, FIGS. 3 to 5 show the internal structure of the gas meter main body 5 of the present invention. FIG. 3 is a front view in which the main body cover 10 and the battery storage cover 11 are removed. A control board 15 is stored in a side where the main body cover 10 is removed, and a battery 16 is stored in a side where the battery storage cover 11 is removed. ing. 17 is the control board 1
5 is a display unit provided in the display unit 5. FIG. 4 shows a state in which the control board 15 is removed from the state shown in FIG. 3, and a two-way valve 1 is provided in a valve block 18 (shown partially cut away) communicating with the inlet-side base 6.
9 and the valve block 18 and the outlet side base 7
Flow path 21 connecting the outlet block 20 communicating with the
Is provided.

FIG. 5 is a cross-sectional view as viewed from the side. The gas meter main body 5 includes a main body cover 10, a battery storage cover 11 and a bottom cover 1.
The control board 15, the battery 16, and the control board 15 are mounted in an air-tight chamber 23 formed by attaching the battery 2 through packings 10 a, 11 a, and 12 a.
The two-way valve 19 and the measurement flow path 21 are housed. Reference numeral 24 denotes a transparent body such as glass which forms the display window 13 of the main body cover 10. The transparent body 24 is airtightly attached to the main body cover 10 with an adhesive or the like. 25 is a gas passage 21
Pressure sensor for measuring the pressure of the outlet block 20
(Not shown). The pressure sensor 25 is provided in an atmosphere opening chamber 28 which is separated from the airtight chamber 23 by a partition 26 and communicates with the atmosphere on the rear surface side of the gas meter main body 5 through an opening 27.
Reference numeral 29 denotes a rear cover provided to prevent dust and the like from entering the open-to-atmosphere chamber 28.

As described above, the inside of the gas meter main body 5 can be formed completely airtight, and at the time of battery replacement, the battery can be easily replaced by removing the battery housing cover 11 from the front where it is easy to work with the pipe installed. it can.

FIGS. 6 to 8 show the control board 15. In the front view of FIG. 6, the display section 17 is arranged at a position facing the display window 13 of the main body cover 10, and on the back side shown in FIG. Has a seismic sensor 30 for detecting an earthquake. The seismic sensor 30 includes a plurality of seismic units 30a, 3a to detect the intensity of the earthquake with a plurality of intensities and perform a control operation according to the detected seismic intensity.
0b is provided. For example, the seismic unit 30a detects the seismic intensity 5 and the seismic unit 30b detects the seismic intensity 6 or more. Here, since it is a ball-type detection unit, a plurality of seismic units 30a and 30b are necessary to detect a plurality of seismic intensity,
If a piezoelectric acceleration sensor (not shown) is applied, it goes without saying that a single seismic sensor can be provided. Reference numeral 31 denotes a microcomputer (hereinafter, referred to as a microcomputer) for controlling the entire system such as calculation of a flow rate, control of a security function, and control of display contents on the display unit 17, and 32 is a signal processing element for measuring a propagation time of an ultrasonic wave. It is. As shown in FIG. 8, when the control board 15 is viewed from the side, a large number of components are arranged on both sides of the board to increase the mounting density and promote the miniaturization of the control board 15 to contribute to the miniaturization of the gas meter. .

FIG. 9 shows a cross section of the measurement flow path 22. The gas flow path 21 is surrounded by a flow path wall 33, and the flow path wall 33 has upstream and downstream ultrasonic transducers 34 and 35. Are installed so as to face each other. The upstream ultrasonic transducer 34 and the downstream ultrasonic transducer 35 are separated from each other by a distance L so as to cross the width W direction of the gas flow path 21 and have an angle with respect to the flow direction of the fluid in the gas flow path 21. It is installed at an angle of θ.

36a, 36b are ultrasonic transducers 34, 3
5 are opening holes on the upstream side and the downstream side, respectively, facing the gas flow path 21. Reference numeral 37 denotes an introduction part provided upstream of the gas flow path 21 and serving as an inlet of the fluid to be measured, and reference numeral 38 denotes a lead-out part provided downstream of the gas flow path 21 and serving as an outlet of the fluid to be measured. 39
Is an inflow suppressing member formed of a mesh or the like provided at the opening of the gas flow passage 21 in the opening holes 36a and 36b.

Numeral 40 is a flow stabilizing means provided on the upstream side of the gas flow path 21. The flow stabilization means 40 is formed of a grid-like direction regulating portion 40a for dividing the cross section of the gas flow path 21 and adjusting the flow direction, and a mesh such as a mesh. A fluctuation suppressing unit 40b. 41
Is a measurement control unit 42 connected to the ultrasonic transducers 34 and 35 for transmitting and receiving ultrasonic waves, a calculation unit 43 for calculating a flow rate based on a signal from the measurement control unit 42 to calculate a flow rate, and various control function units. It is a control part provided with. This control unit 41 is housed in the signal processing element 32.

Next, the operation of the ultrasonic flow measuring device will be described. The flow of the fluid to be measured flowing from the introduction part 37 is regulated by the flow stabilizing means 40 provided on the inlet side of the gas flow path 21 and the velocity fluctuation is stabilized.

Next, the operation of measuring the flow rate using ultrasonic waves will be described. In the gas flow path 21, an ultrasonic wave is applied to the stabilized flow so as to cross the width W of the flow path cross section of the gas flow path 21 between the ultrasonic transducers 34 and 35 by the operation of the measurement control unit 42. Transmission and reception are performed. That is, the propagation time T1 until the ultrasonic wave emitted from the ultrasonic wave transducer 34 on the upstream side is received by the ultrasonic wave transducer 35 on the downstream side is measured. On the other hand, the propagation time T2 until the ultrasonic wave emitted from the ultrasonic wave transducer 35 on the downstream side is received by the ultrasonic wave transducer 34 on the upstream side is measured.

Based on the propagation times T1 and T2 measured in this way, the flow rate is calculated by the calculation unit 43 by the time difference method shown in the following calculation formula.

The angle between the flow velocity V of the fluid to be measured in the gas flow path 21 and the ultrasonic wave propagation path P is θ, the distance between the ultrasonic transducers 34 and 35 is L, and the fluid to be measured is L. Assuming that the sound velocity is C, the flow velocity V is calculated by the following equation.

T1 = L / (C + Vcosθ) T2 = L / (C−Vcosθ) The sound velocity C is deleted from the formula for subtracting the reciprocal of T2 from the reciprocal of T1 and V = (L / 2cosθ) ((1 / T1) − (1 / T2)) Since θ and L are known, the flow velocity V is calculated from the values of T1 and T2.
Can be calculated. Based on the measurement result, the display unit 17 displays a flow value and the like via the microcomputer 31.

If the sing-around method is used, more accurate measurement can be performed. In addition, since the flow rate measurement by the ultrasonic wave has a high time resolution, it can be measured up to a minute low flow velocity region, and a leak at a flow rate of 3 L / h can be detected. For this reason, it was possible to measure from a very small flow rate of 3 L / h to a large flow rate approximately twice as large as the maximum flow rate required for the conventional gas meter, and the measurement range of the No. 6 meter could be satisfied. The number of meters can be shared.

By the way, the flow velocity V obtained as described above
Is measured in the ultrasonic wave propagation path obliquely crossing the gas flow path 21. Since the average flow velocity measured in the ultrasonic wave propagation path differs depending on the cross-sectional position, the flow rate is calculated by adding a correction coefficient. From the cross-sectional area S orthogonal to the flow direction of the ultrasonic transducers 34 and 35, the flow rate Q is: Q = KVS where K is a flow coefficient in consideration of the flow velocity distribution in the cross-sectional area S.

In this way, the flow rate can be obtained by the calculating section 43.

FIG. 10 shows the flow rate change characteristics of the flow coefficient. The laminar flow area with a small flow rate, the turbulent flow area with a large flow rate,
In the transition region where the flow shifts from the laminar flow region to the turbulent flow region, the flow velocity distribution in the gas flow path 21 changes, so that the flow coefficient changes. In the ultrasonic measurement, this flow coefficient curve can be obtained as a smooth curve irrespective of a change in temperature and a change in gas type. By introducing this flow coefficient, as shown in FIG. 11, a sufficient verification tolerance (Qmax to 0.1Qmax is ± 1.
It is possible to obtain an instrument difference characteristic that satisfies 5% and 0.1 Qmax to Qmin is ± 3%.

FIG. 12 shows a measurement flow path 2 having a gas flow path 21.
2 is a sectional view showing the upstream side and the downstream side of FIG. In the figure, a valve block 4 provided with a two-way valve 19 has a valve body 4.
A valve seat 45 is provided at a position opposing the valve seat 4.
An introduction passage 46 that communicates with the introduction section 37 is provided downstream of 5. Reference numeral 47 denotes an inflow passage communicating with the inlet-side base 6. 48 is a spring for urging the valve body 44 in the direction of the valve seat 45, and 49 is a drive unit such as a solenoid or a motor for driving the valve body 44 to open or close.
The outlet block 20 disposed on the downstream side of the measurement flow path 22 is provided with a lead-out passage 50 having one end communicating with the lead-out portion 38 and the other end communicating with the outlet-side base 7.

FIG. 13 is a sectional view showing the structure of the two-way valve 19, in which the drive unit 49 is a stepping motor, and the rotor 5 has a magnetic pole 51 of a permanent magnet on the outer periphery.
2 and a stator 54 surrounding the excitation coil 53 and formed of a magnetic material. Reference numeral 55 denotes a rotor rotation shaft provided on the rotor 52.
In this embodiment, a male screw with a spiral groove (or projection) is used as the feeding means 56. 5
Reference numeral 7 denotes a moving body provided with a female screw to be screwed into the feeding means 56, and 58 denotes a rotation preventing body for preventing the moving body 57 from rotating with respect to the rotor rotation shaft 55. 59 is a moving body 57
A spring interposed between the valve body 44 and the valve body 44 to apply an urging force to separate them from each other in the axial direction.
4 generates a force for pressing the valve seat 4 against the valve seat 45. Reference numeral 60 denotes a partition wall for airtightly separating the rotor 52 on the fluid side and the valve body 44 side and the stator 54 side connected thereto. Reference numeral 61 denotes a support shaft that supports the rotation of the rotor 52. 62 is the valve body 44
The position detecting sensor detects the moving position of the valve body 44.
Is in contact with the valve seat 45 to detect that the valve is in the valve closed state, and the valve body 44 is completely moved to the drive unit 49 side to detect that the valve is in the fully open position. It is provided with a valve fully open position detecting section 62b. Numeral 63 denotes a position transmitting section provided on the valve body, which detects the position when the valve closing position detecting section 62a or the valve fully open position detecting section 62b and the position transmitting section 63 come close to each other and coincide with each other. Therefore,
By confirming the position of the valve body 44 and performing the feedback control, the valve can be reliably closed and opened.

FIG. 14 is a flowchart of the bidirectional valve operation performed by the control unit 41. In FIG. 14, reference numeral 64 denotes an abnormality detection instruction, 65 denotes a valve driving instruction, and 66 denotes a valve closing detection instruction.

Next, the operation and operation will be described. Now
Assume that the flow measurement value becomes an abnormal value. In FIG. 14, the valve drive command 65 is instructed by the abnormality detection command 64, and the valve moves in the closing direction. When the movement is completed, a valve closing detection command is executed.

FIG. 15 is a flowchart of the seismic operation performed by the control unit 41. In FIG. 15, reference numeral 67 denotes a seismic sensor signal input command, and reference numeral 68 denotes a seismic intensity determination command. 69 is a non-execution instruction of the two-way valve, and 70 and 71 are immediate shutdown instructions. 72 is a return determination instruction of the two-way valve, 73 is a return instruction,
Reference numeral 74 denotes a shut-off continuation command.

Next, the operation and operation will be described. Now
Suppose that the seismic sensor was activated by the earthquake. At this time, a signal is input by a seismic sensor signal input command 67, and a seismic intensity determination is performed by a seismic intensity determination instruction 68.

As a result of the determination, when the seismic intensity is smaller than 5, the shut-off non-execution instruction 69 does not shut off the two-way valve. When the seismic intensity is 5, it is shut off by the immediate shutoff command 70. Thereafter, if the return is possible by the return determination instruction 72, the two-way valve is opened again by the return instruction 73, and the automatic return is performed. In the case where it is not possible to return, the interruption continuation instruction 7
4, the cutoff state is continued.

If the result of the seismic intensity determination indicates that the seismic intensity is 6 or more, the immediate cutoff command 71 is executed, and in that case, the automatic return is disabled and the state is maintained.

FIG. 16 is a flowchart of the individual maximum flow rate determination operation performed by the control unit 41. In FIG.
5 is a flow rate measurement command, 76 is an individual maximum flow rate determination command, 77
Is a shutdown command. 78 is an interval setting command.

Next, the operation and operation will be described. Now
It is assumed that the value measured by the flow rate measurement command 75 is equal to or greater than the individual maximum flow rate value determined by the number of the meter. At this time, the determination by the individual maximum flow rate determination command 76 is Ye
On the s side, the gas is stopped by the shutoff command 77 of the two-way valve. If the value measured by the flow rate measurement command 75 is smaller than the individual maximum flow rate value, then the determination by the individual maximum flow rate determination command 76 is No, and after the interval setting command 78, Flow measurement is performed.

FIG. 17 is a flowchart of the appliance discriminating operation performed by the control unit 41. In FIG. 17, 79 is a flow pattern measurement command, 80 is a tool discrimination command, 81 is a tool specifying command, and 82 is a tool condition selection command. 83 is an interval setting command.

Next, the operation and operation will be described. Now
Suppose a gas appliance is being used. At this time, the flow pattern of the device is measured by the flow pattern measurement command 79. Next, the appliance identification command 80 compares the used appliance with the already registered pattern, and if there is a corresponding one, the appliance identification instruction 81 specifies the appliance.
Thereafter, the condition corresponding to the device is set by the device condition selection command 82.

If there is no corresponding appliance in the appliance discriminating instruction 80, the process branches to No, passes through the interval setting instruction 83, and returns to the original routine again.

In the above-described embodiment, the so-called Z-pass type is shown as the configuration of the ultrasonic measurement, but the present invention is not limited to this. A method of measuring using a propagation time difference such as an I path and a W path is also possible.

In addition, the gas meter is provided with the base at the upper part as an installation form.
It is also possible to be on the side.

As described above, the gas meter according to the present embodiment measures the flow rate using ultrasonic waves, and thus has the following effects.

For example, it can be used both indoors and outdoors, the environment used is a storage temperature range of -30 ° C. to + 70 ° C., the operating temperature is within a range of -25 ° C. to + 55 ° C.
The following effects are obtained under the condition of humidity of not more than% (both conditions with and without dew condensation). In addition, 20 as a gas meter
It is assumed that the condition that the battery can be used for more than a year (however, the battery serving as a power source is replaced every 10 years) is satisfied.

(1) In addition to being able to detect a minute leak of 3 liters / h, it is also possible to distinguish between 0 liters / h and 3 liters / h. Therefore, the following minimum flow rates can be used with a margin of 25 liters / h for the No. 4 meter and 40 liters / h for the No. 6 meter, and can be used without changing the hardware configuration. Can respond.

(2) Accuracy within the instrumental error range can be secured as a gas meter. (A) A monotonically increasing output is obtained up to twice the maximum flow rate as well as 0 to the minimum flow rate. ± 3
% Error range (measured at a flow rate of 4/3 times the maximum flow rate, a flow rate of 5/3 times the maximum flow rate, and a flow rate of 2 times the maximum flow rate). The error up to the flow rate of ± 3% (when measured at the minimum flow rate and three times the minimum flow rate), and the error from 0.1 times the maximum flow rate to the maximum flow rate is ± 1.5% (maximum) 0.1 times, 0.2 times, 0.4 times, 0.7 times, and the maximum flow rate of the flow rate), and the instrumental error curve is 0.1 times the maximum flow rate to the maximum of the maximum flow rate. And the minimum is 2%, the actual ability does not exceed 1%, and even if the measurement is performed three times in the upward and downward directions, the error is 1% range and the maximum is 0.1 times the minimum flow to the maximum flow. 0 of flow rate.
The error between the single flow rate and the maximum flow rate falls within the range of 0.6%. The above-mentioned accuracy can be obtained even when the gas meter is installed in the inclination range of ± 5 °. Further, the individual difference between the gas meters does not exceed 1%.

(B) The pressure loss in the air at the maximum flow rate can be reduced to 180 Pa or less even with the shut-off valve included.

(C) Even in a wide temperature range of -25 ° C. to + 55 ° C., the error from the minimum flow rate to the flow rate 0.1 times the maximum flow rate is ± 3%, and the flow rate is 0.1 times the maximum flow rate to the maximum flow rate. Up to ± 1.5%.

(D) Even if the gas composition fluctuates within the range of, for example, 13 A, the error from the minimum flow rate to the flow rate 0.1 times the maximum flow rate is ± 3%, and the flow rate is 0.1 times the maximum flow rate. Up to the maximum flow rate is within the range of ± 1.5%.

(E) The structure is resistant to dust. That is, after the dust test, the flow rate falls within the range of -7% to + 4% in the range of the flow rate from 0.05 to the maximum flow rate, and within the range of ± 4% in the range of the flow rate from 0.05 to the maximum flow rate to the maximum flow rate. Practically, within the range of the minimum flow rate to 0.1 times the maximum flow rate, it is within ± 3%, and within the range of 0.1 times the maximum flow rate to the maximum flow rate, it is within ± 1.5%. At this time, the pressure loss at the maximum flow rate is 180 Pa or less including the shut-off valve, and the pointer does not move at 0 liter / h, and becomes less than ± 1 liter in one hour.

(F) The structure is resistant to mist. That is, in the range of the minimum flow rate to 0.05 times the maximum flow rate, it falls within the range of -7% to + 4%, and in the range of the flow rate of 0.05 times the maximum flow rate to the maximum flow rate, it falls within the range of ± 4%. ± 3% in the range of minimum flow rate to 0.1 times the maximum flow rate,
In the range of 0.1 times the maximum flow rate to the maximum flow rate, ± 1.
It falls within the range of 5%.

(G) The configuration is resistant to pressure fluctuations. That is, even when the gas heat pump is operated in the upstream neighbor or the gas heat pump is operated in the house, in the range of the minimum flow rate to 0.05 times the maximum flow rate, -7 to
+ 4%, within the range of 0.05 times the maximum flow rate to the maximum flow rate, within ± 4%, practically within the range of the minimum flow rate to 0.1 times the maximum flow rate, ± 3%, maximum In the range from 0.1 times the flow rate to the maximum flow rate, it falls within the range of ± 1.5%. At 0 liter / h at that time, the pointer does not move, and in one hour, it is less than ± 1 liter. At 3 liters / h, the pointer advances, and the flow rate is measured. In this case, it is arranged not to reset the gas pipe leakage warning.

(3) A compact configuration has become possible.
For example, vertical 130mm or less (excluding the base), horizontal 180
The outer dimensions of less than 90 mm and a depth of 90 mm or less can be realized.

(4) Switching display between integrated flow rate display and instantaneous flow rate display becomes possible.

(5) The pulse display accuracy at the time of the test is improved. For example, 0.1 liter / pulse at the time of verification, 1 at normal time
It can be liter / pulse.

(6) Bidirectional shutoff can be performed by using a bidirectional shutoff valve, and the open / closed state can be reliably detected by providing a feedback control function.

(7) The control board, the battery, and the sensor can be mounted in an airtight structure, and the battery can be replaced on site.

(8) Both the inlet and the outlet are in the vertical direction, the upper left side is the inlet, and the upper right side is the outlet.

(9) The security function as a gas meter is improved. That is, (a) the determination time can be shortened, for example, the individual maximum flow rate determination time can be reduced to 10 seconds or less, and the safety is improved.

(B) Accuracy can be determined in a short time.

(C) By determining the equipment to be used, it is possible to change the duration of the interruption for the continuous time and to determine whether or not the interruption is performed.

(D) By adopting a multi-stage seismic sensing function, etc., it is possible to deal with each seismic intensity. For example, the seismic intensity 5 and the seismic intensity 6 or more are discriminated, and when the seismic intensity 5 is detected, immediate cutoff and automatic return can be performed, and when the seismic intensity 6 is detected, immediate shutoff and no automatic return can be performed.

[0061]

As is apparent from the above description, according to the present invention, the gas flow rate is measured using ultrasonic waves, so that accurate flow rate measurement can be performed, and the use of ultrasonic waves makes the apparatus compact. Can be configured.

[Brief description of the drawings]

FIG. 1 is a front view showing a gas meter installed state of the present invention.

FIG. 2 is a side view showing an installed state of the gas meter of the present invention.

FIG. 3 is a front view showing the internal configuration of the gas meter of the present invention.

FIG. 4 is a front partial sectional view showing the internal configuration of the gas meter of the present invention.

FIG. 5 is a partial side sectional view showing the internal configuration of the gas meter of the present invention.

FIG. 6 is a front view of a control board of the gas meter of the present invention.

FIG. 7 is a back view of the control board of the gas meter of the present invention.

FIG. 8 is a side view of a control board of the gas meter of the present invention.

FIG. 9 is a cross-sectional view of a measurement flow path of the gas meter of the present invention.

FIG. 10 is a flow rate change characteristic diagram of a flow coefficient of the gas meter of the present invention.

FIG. 11 is an instrumental difference diagram of the gas meter according to the present invention.

FIG. 12 is a sectional view of a fluid passage of the gas meter of the present invention.

FIG. 13 is a sectional view of the configuration of a two-way valve.

FIG. 14 is a flowchart of a two-way valve operation.

FIG. 15 is a flowchart of the seismic sensor operation.

FIG. 16 is a flowchart of an individual maximum flow rate determination operation.

FIG. 17 is a flowchart of an appliance determination operation.

FIG. 18 is a configuration diagram of a conventional membrane gas meter.

[Explanation of symbols]

 Reference Signs List 18 valve block 19 two-way valve 20 outlet block 21 gas flow path 22 measurement flow path 30 seismic sensor 34, 35 ultrasonic transducer

Claims (1)

[Claims] A gas flow path, an ultrasonic transducer provided for measuring a flow rate of a gas flowing through the gas flow path, and a gas flow rate measured based on an output from the ultrasonic transducer. Gas meter consisting of a control unit.