JP3374362B2 - Gas meter - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas meter,
In particular, the present invention relates to a gas meter that can automatically determine the gas type and can also automatically correct a measurement error that differs for each meter.

[0002]

2. Description of the Related Art Membrane gas meters have been used as gas meters that have been widely and conventionally used. This membrane-type gas meter has a membrane that repeats vibration due to the pressure of the gas flow inside its housing, and the gas flow rate is measured in response to the volume change due to the vibration of the membrane. It is a meter that directly measures the volume of the gas by using its operation. Due to its simple and practical structure and high durability, it has been widely used. On the other hand, however, such a conventional membrane-type gas meter also has a characteristic of being mechanical as described above, and therefore, the microcomputer of recent years (hereinafter,
There is an inconvenience that it is difficult to adapt to the digitization of a gas meter using a microelectronic circuit such as a microcomputer.

Here, the gas meter is roughly classified into a method of directly measuring the amount of gas mechanically such as the above-mentioned membrane type gas meter, and a physical value as a fluid of a gas flow such as a flow velocity of gas. However, a so-called speculative gas meter has been devised, in which the numerical value of the gas flow rate is calculated by a calculation circuit such as a CPU of a microcomputer in accordance with the measured value.

That is, since the speculative gas meter handles the numerical value of the gas flow rate as an electric signal from the measuring stage, the gas flow rate value can be transmitted, processed and stored as a data signal even after the measurement. Therefore, since it has a characteristic that it is extremely well adapted to a system for performing such data management, it is attracting attention as a particularly suitable technique in a gas meter which has been digitized in recent years.

In such a stochastic gas meter, the number of revolutions of the turbine due to the gas flow is counted by a device such as a rotary encoder, including an ultrasonic measurement method using the difference in the propagation time of ultrasonic waves. Turbine measurement method such as calculating the value of gas flow rate by using a differential pressure measurement method that uses the pressure difference at two points caused by gas flow.
Several types of methods have been proposed, but all of them are attracting attention because they can accurately measure the gas flow rate with a continuous value.

Among them, the ultrasonic measuring method is particularly known as a technique capable of measuring an accurate flow rate while having a small size and a simple structure. Ultrasonic measurement type gas meter,
As shown in an example of the outline of the structure in FIG. 7, a partition wall 503 that divides an airtight chamber formed in an airtight structure into two chambers, that is, a first chamber 501 and a second chamber 502, and a gas pipe 504 on the upstream side. An inlet 506 connected to introduce the gas 505 into the first chamber 501, an outlet 508 connected to the gas pipe 507 on the downstream side to deliver the gas 505 from the second chamber 502, and the partition wall 503. Gas from the first chamber 501 to the second chamber 502.
To measure the flow rate of the gas 505 based on the value of the flow rate, which is a fluid physical quantity of the cylindrical gas conducting path 509 that passes through the gas flow channel 05 and the gas 505 that passes through the gas conducting path 509. A main part is formed of an ultrasonic oscillator 510 and a geophone 511 which are arranged to face each other in a direction parallel to the gas flow with a predetermined length.
The ultrasonic measurement type gas meter can accurately measure the gas flow rate with such a relatively simple structure.

[0007]

However, the gas conduit 5 which is the main part for measuring the gas flow rate used in the conventional gas meter of the ultrasonic measurement type as described above.
09, the ultrasonic oscillator 510, and the geophone 511, the so-called ultrasonic type gas flow rate measuring tube is generally suitable for measuring a gas flow rate as a gas meter because of its characteristic that the gas flow rate can be accurately measured. The gas flow velocity measuring tube whose performance or specification is determined in advance in a specific range and does not meet this or has a large error is useless.

Therefore, it goes without saying that if the gas meter does not meet the optimum value determined for each type of gas used, or if there is a large error with respect to it, it will be verified as a defective product when verifying the measurement performance. However, in terms of performance (specification) such as the number of gas meters, a gas meter equipped with a gas flow rate measuring tube manufactured to meet one type can be used only for that type of gas meter. . Therefore, it is necessary to prepare various kinds of gas flow rate measuring tubes so as to meet the requirements of diversifying gas meter specifications.

In order to match the specifications of the gas meter to the optimum performance for each kind of gas, hardware such as an ultrasonic wave oscillator 510 and a geophone 511 used in the gas meter, such as electronic parts and mechanical parts. Is replaced with an optimal specification for each type of gas, or when the data measured by hardware such as the ultrasonic oscillator 510 and the geophone 511 is processed by the arithmetic processing circuit system. There are two possible modification methods, in which the calculation method used for data processing is corrected to the optimum one using software, but in any case, after the gas meter is completed as a product, the It is not easy to change specifications, and also to change them externally.

Although it is considered that the change on the software is simpler than the change on the hardware, actually, the specifications regarding the main part of the function of the gas meter, which is a measuring instrument, can be easily changed from the outside. This means that there are many practical inconveniences, and problems that are difficult to solve, such as the possibility that the gas may be used in an illegal measuring method by intentionally changing the specifications. There is.

As described above, according to the conventional technique, the gas meter has to be designed so as to optimally match one type of gas, and cannot be practically used for other types of gas. Therefore, in response to diversifying gas meter specifications, it is necessary to prepare various types of gas flow rate measurement tubes that meet each of them, and gas meters are extremely complicated in terms of performance or specifications. There was a problem of inviting.

The present invention has been made to solve such a problem. An object of the present invention is to realize a gas meter that can meet various types of performance requirements with one type of hardware and software structure.

[0013]

First, a gas meter of the present invention comprises a gas fluid data measuring means for measuring data of a fluid physical quantity of a gas flow, and a function for associating the physical quantity data with a gas flow rate. A gas meter of a stochastic system having a gas flow rate calculating means for calculating the gas flow rate of the gas from the data of the fluid physical quantity of the measured gas flow, when the gas flow is stopped. A gas kind discriminating means for discriminating the kind of the gas based on the measured data by propagating the ultrasonic wave to the stopped gas, measuring the propagation time data of the ultrasonic wave,
Based on the corrected function, a function correction unit that corrects the function so as to match the determined gas type, and the gas of the gas flow from the data of the fluid physical quantity of the measured gas flow. A gas flow rate calculation means for calculating a flow rate , and the gas type determination means is switched from the outside.
Equipped with an ON / OFF switch
Only when the is turned on, the type of gas is determined
It is characterized in that it is a gas type discriminating means .

That is, data including a physical quantity relating to the propagation time of an ultrasonic wave, such as a propagation time at that time or a singaround frequency which is the reciprocal of the propagation velocity, in the dimension when the ultrasonic wave is propagated to a gas that is stopped. Can be measured and the type of gas can be determined based on such data relating to the propagation time. Then, the function that associates the physical quantity data with the gas flow rate is corrected so that the optimum gas flow rate can be calculated for the determined gas type.

In this way, according to the present invention, the software change can be automatically performed mainly in accordance with the gas type. Also, one type of gas meter can be used. The measurement method of the fluid physical quantity of the gas flow described above, that is, the measurement method of the gas fluid data measuring means applicable to the present invention includes ultrasonic measurement method and other methods. Vortex measurement method that generates gas and calculates the gas flow rate from the generation speed of the vortex, turbine method that calculates the gas flow rate by measuring the rotation speed of the turbine blade placed in the gas flow, and static measurement using a Pitot tube, etc. Differential pressure measurement method that measures gas flow differential pressure against pressure to calculate gas flow rate, heat ray measurement method that calculates gas flow rate by measuring cooling degree by gas flow such as heating wire placed in gas flow, An inference method such as an area method in which the differential pressure of the gas flow is kept constant and the area of a throttle placed in the gas flow is changed to measure the gas flow rate can be applied. Gas
Normally, when installing a meter and connecting it to the gas pipe,
The gas is off. Or abnormal stop gas
Even if it is a battery, install the gas meter and use it.
At the start, the anomaly detection system stops the gas flow.
It should be stopped. Therefore, such gas
Function of the gas type determination function when installing
When necessary, gas flow stops in the gas meter.
Are detected by, for example, gas fluid data measuring means.
Then, the microcomputer automatically operates the gas type determination means.
Generated, or gas stop of the above abnormality detection system
In conjunction with the operation ON, the gas type discrimination means is also turned ON.
By switching the gas type discriminating means,
And determine the type of gas that will be used
However, the gas type discriminating means is automatically turned on in this way.
When turning N / OFF, it is not necessary to determine the gas type.
Even when there is no gas type determination means will operate,
It is possible that the operating current for that amount is wasted. In particular,
In recent years, the life of one gas meter has been extended to 7 to 15 years.
Therefore, the power supply system such as batteries cannot withstand continuous use during this period.
Getting to get is not easy. Therefore gas meter
It is necessary to minimize waste of operating current inside as much as possible.
Be contracted. Therefore, in such a case,
Switching operation can be ON / OFF from the outside as in the technique
When a switch is attached and gas type discrimination means is needed
It should be activated.

Secondly, the gas meter of the present invention comprises the above first
In the gas meter according to item 1, the gas fluid data measuring means is arranged so as to face each other with a gas conduction path formed so that the gas flow passes through the inside of the cylinder, and ultrasonic waves are introduced into the gas flow inside the cylinder. Equipped with an ultrasonic oscillator and an ultrasonic receiver for detecting the physical quantity of the propagated ultrasonic wave, and measuring the fluid physical quantity data of the gas based on the propagated ultrasonic wave physical quantity data. , A gas fluid data measuring unit for calculating the gas flow rate based on the data, wherein the gas type determining unit includes the ultrasonic oscillator and the ultrasonic geophone for propagating ultrasonic waves to the gas in the stopped state. It is a gas meter characterized by being a gas type discrimination means to be used.

That is, the gas type discriminating means according to the present invention is
The ultrasonic wave is propagated to the gas to measure its propagation time. On the other hand, in the gas meter described in the second aspect, the gas fluid data measuring means also propagates the ultrasonic wave to the gas to measure a physical quantity such as its propagation time. Is a gas fluid data measuring means of a so-called ultrasonic measurement method for measuring the. Therefore,
Since these are common in the function of propagating ultrasonic waves to the gas, this is skillfully utilized to make the ultrasonic oscillator and ultrasonic geophone of the gas fluid data measuring means,
It can also be used as a gas type determination means.

Moreover, at this time, the gas fluid data measuring means functions as a means for measuring the gas flow rate when the gas is flowing, and the gas type determining means functions when the gas is stopped. Even if both the ultrasonic oscillator and the ultrasonic geophone are used, the inconvenience that both functions are required at the same time cannot occur at all. Therefore, according to the technique of the present invention, the ultrasonic oscillator and the ultrasonic geophone can be suitably combined.

As described above, since the ultrasonic oscillator and the ultrasonic geophone can be used also as the gas type discriminating means,
It is possible to effectively realize simplification of the structure while sufficiently satisfying the predetermined function.

[0020]

[0021]

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a gas meter according to the present invention will be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 is a diagram showing an outline of the configuration of a gas meter according to a first embodiment of the present invention. The gas meter 1 of this embodiment measures the flow velocity of a gas flow as a fluid physical quantity of a gas flow by measuring the propagation time T of an ultrasonic wave propagating in the gas flow, which is a gas fluid data measuring means 101. And a gas flow rate ΔV = Fx (T) per specific unit time from the data of the propagation time T based on a function Fx that associates the measured propagation time T data with the gas flow rate ΔV. Further, the gas flow rate calculation means 10 for calculating the integrated flow rate V of the gas by further integrating this over time.
4 is a stochastic gas meter. Further, in the gas meter 1, when the gas flow rate calculation means 101 measures that the gas flow is stopped,
A gas type discriminating means 102 for discriminating the gas type Gx based on the measured data (t) by propagating an ultrasonic wave to the stopped gas, measuring data of the propagation time t of the ultrasonic wave. , Function correcting means 1 for correcting the function Fx so as to match the gas type Gx thus determined
03 and the function Fx corrected in this way, from the data of the propagation time T, the gas flow rate ΔV =
A gas flow rate calculation means 104 for calculating Fx (T) and further integrating it to calculate a gas integrated flow rate V is provided in its main part. In addition, the above gas flow rate calculation means 10
The display means 105 for displaying the value of the integrated gas flow rate V calculated by No. 4, and the value of the integrated gas flow rate V, which is installed in an external gas company or the like, via a transmission path 106 such as a telephone line. A transmission / reception means 107 for transmitting / receiving data to / from a data management system (not shown) is provided.

The gas fluid data measuring means 101 is
As shown in FIG. 2, a gas passage 301 is formed in a cylindrical shape so that a gas 302 passes through the inside of the cylinder, and a gas 30 in the gas passage 301 is arranged so as to face each other.
Ultrasonic wave transmitter / receiver 303, 3 for propagating ultrasonic waves in 2
04, and the propagation time T is measured.

The gas type discriminating means 102 also uses the above-mentioned ultrasonic wave generators / receivers 303 and 304 also in this case, and propagates ultrasonic waves to the gas 302 being stopped. In addition, an abnormality detection system 201 for detecting an abnormal situation of the gas flow and stopping the gas flow is also provided.

FIG. 2 is a diagram schematically showing an example of a case where each unit in this embodiment as described above is built around the CPU 100. As shown in FIG. 2, the airtight chamber 200 has a gas passage 301 in which a gas 302 flowing from an intake 202 on the upstream side is installed in the airtight chamber 200.
Through the gas delivery port 203 on the downstream side, and is delivered to gas equipment (not shown) outside the gas meter.

As shown in the figure, the gas communication path 301 includes ultrasonic wave transmitters / receivers 303, 304 arranged by a so-called Z method, that is, an oblique arrangement method with respect to the center line of the gas communication path 301. The ultrasonic wave transmitter / receiver 303, 30 has a propagation time t during which the ultrasonic wave propagates between them.
I / F (interface) of the electrical signal detected in 4
The CPU 100 receives the data via the circuit 400, processes it, and converts it into data.

A CPU is installed in the intake 202 on the upstream side.
When the CPU 100 detects an abnormal situation, an abnormality detection system 201 including a shutoff valve 204 that is controlled by the CPU 100 to forcibly stop the inflow of gas is installed. The main part of the gas meter of this embodiment has a hardware configuration as shown in the actual view of FIG. It is the ultrasonic wave transmitter / receivers 303 and 304 that perform the ultrasonic wave oscillation-reception on the hardware in the gas fluid data measuring means 101, but the electrical signals detected by them are converted into data, and A circuit system or the like for processing the propagation time T on the basis of data can be actually constructed inside the CPU 100.

Similarly, in the gas type discriminating means 102 described above, it is the ultrasonic wave transmitter / receivers 303 and 304 that perform the oscillation to the vibration reception of the ultrasonic waves on the hardware, but the signals detected by them. The means for arithmetically processing the propagation time t based on the above can be built inside the CPU 100.

The functions required for the function correcting means 103, the gas flow rate calculating means 104, and the transmitting / receiving means 107 are data processing functions.
It can be built inside 100. Also, the transmission path 1
No. 06 uses a telephone line in this embodiment. As the display means 105, in the present embodiment, a segment type small liquid crystal display device for displaying the numerical value of the integrated gas flow rate is used.

Next, the outline of the operation of the gas meter of the first embodiment according to the present invention having the above-mentioned outline structure will be described based on the outline flow chart of FIG. First, when this gas meter is newly installed, the air inside the airtight chamber 200 has been filled up to that time, so the air must first be replaced with gas. Therefore, after the gas meter is connected to the gas pipe, the air inside the gas meter is replaced with the gas, and after the gas is completely replaced with the gas, the power switch of the gas meter is turned on and the CPU 100 starts the operation.

When the power switch is turned on, the gas fluid data measuring means 101 and the gas flow rate calculating means 104 start measuring the propagation time T of ultrasonic waves in the gas (s1).
Then, based on this propagation time T, the gas type determination unit 102 detects whether or not the flow of the gas 302 is stopped (s2).

As a method of detecting the gas flow stop, for example, both the ultrasonic wave generator / receiver units 303 and 304 are provided with the functions of both the receiver unit and the oscillator, and the ultrasonic wave generator / receiver unit 30 is used.
The difference ΔT between the propagation time of the ultrasonic wave from 3 to the ultrasonic wave transmitting / receiving device 304 and the propagation time of the ultrasonic wave from the ultrasonic wave transmitting / receiving device 304 to the ultrasonic wave transmitting / receiving device 303 is measured.

When this ΔT is ΔT = 0, the ultrasonic transmitter / receiver 303 and the ultrasonic transmitter / receiver 304 are used.
It means that the gas, which is the medium of ultrasonic waves, has stopped between and. By measuring ΔT = 0 in this way,
The stop of the flow of the gas 302 can be detected.

Alternatively, in general, when a gas as a medium is flowing, ultrasonic waves propagating in the gas as a medium should be observed due to the influence of the Doppler effect to change the frequency and the like. Is. Therefore, it may be possible to detect whether the gas is stopped by using such a phenomenon.

When ΔT detected in this way is ΔT = 0, that is, when the flow of the gas 302 is stopped (Y in s2), the gas type discriminating means 102 causes the ultrasonic oscillator 303 to transmit the ultrasonic receiver 304. The propagation time t of the ultrasonic wave to the is measured (s3). Then, the gas type determination means 102 determines the gas type Gx based on the measured propagation time t (s4).

Here, in general, the speed of sound changes according to the physical characteristics of the medium. Considering the sound velocity v of perfect gas, the sound velocity v is proportional to the square root of (κp / ρ). Where κ is the specific heat ratio of the gas, p is the pressure of the gas, and ρ is the density of the gas. That is, in general, the sound velocity v changes corresponding to the physical characteristics such as the specific heat ratio of the gas (the gas 302 in the present invention) which is the medium, the pressure, and the density. If they are different,
Correspondingly, the sound velocity v should be different for each type Gx of the gas 302.

Therefore, if the distance (L) between the ultrasonic oscillator 303 and the ultrasonic geophone 304 and the frequency of the ultrasonic waves are fixed, the propagation of the gas 302 in the gas 302 at rest during the distance is fixed. By measuring the time t, the sound velocity v = L / t can be obtained based on this. Then, the gas type Gx can be specified (determined) based on the obtained sound velocity v.

For example, the gas density of ethane which is the main component of city gas (ρ above) is ρ = 1.280, and the gas density of propane which is the main component of propane gas is ρ = 1.8.
95. As is clear from this example of ρ, since the physical quantity that influences the sound velocity v has a value that is considerably different for each gas type, it corresponds to the sound velocity v or the propagation time t that is the original data from which it was calculated. Therefore, the gas type Gx can be accurately specified. Alternatively, the application of the technique of the present invention is not limited to the above-described discrimination of the types of gas for thermal energy applications such as city gas and propane gas. In addition to this, for example, it can be applied to a gas flow meter or the like that automatically and accurately determines a medical gas for which security accuracy is required and then measures it. That is, the gas used as medical gas mainly includes anesthesia gas, oxygen and other gases, but it is necessary to measure and display an accurate value of the gas flow rate after distinguishing the types of these gases. The present invention can also be applied to a gas meter.

As an example of the value of t thus measured, according to the experiment of the inventor of the present invention, the ultrasonic wave transmitter / receiver 3
When the distance L between 03 and 304 was L = 150 mm, the propagation time t of the ultrasonic wave was about 650 μs in air and about 500 μs in methane. As described above, since the propagation time t of the ultrasonic wave in the gas at rest is obviously different depending on the type of gas, it is possible to measure this propagation time t and specify the gas type Gx corresponding to this t. it can.

In this way, when the gas type discriminating means 102 discriminates the gas type Gx based on the propagation time t (s4), the function correction is performed based on the correction method preset for each gas type Gx. The means 103 corrects the function Fx (s5). A method of correcting this function Fx will be described. The horizontal axis represents the reference value of the standard prototype used for the verification of the gas meter 1 as a measuring instrument, that is, the reference value of the gas flow rate when it is correctly measured, and the error (%) is taken on the vertical axis. , When plotting the graphs, those graphs show that the gas type G
All of the different types of gas such as a, Gb, Gc ... Are deviated from the reference value (horizontal axis).

Therefore, for example, the gas meter 1 of this embodiment
Is required to match the gas type Ga, the function Fx (T) must be corrected so that the graph of the gas type Ga overlaps the reference value (horizontal axis).
Here, the correction method will be described in more detail. The gas flow rate calculation means 104 corresponds to the measured propagation time T of the ultrasonic wave and functions Fx (T); ΔV = Fx.
The gas flow rate ΔV is calculated based on (T). This calculation is actually executed inside the CPU 100 shown in FIG. 2, but at this time, the correspondence from T to ΔV; T → ΔV is the CPU 1
00 storage element or EEPR attached to it
This is executed based on a table stored in advance in a storage element such as an OM (none of which is shown), for example, the data content of which is schematically shown in FIG.

That is, the function Fx (T) is actually CP
Based on the table Fx recorded in U100 or the storage element attached to U100, ΔV is applied to the variable T.
Is synonymous with performing the operation of associating with. That is, correcting the function Fx (T) is, in other words, corresponding;
This is synonymous with correcting the table of T → ΔV.

Therefore, in the present embodiment, the function Fx
As a more specific method of (T), the gas type G
Optimal correspondence for each of a, Gb, Gc, etc .; a table capable of calculating T → ΔV is prepared respectively, and the gas type Gx is discriminated by the gas type discriminating means 102 (s4). Gas types Ga, Gb,
The function correction means 103 selects and reads the table Fx suitable for the gas type Gx from the tables Fa, Fb, Fc, ... For each Gc. For example, when the gas type is Ga, the table Fa corresponding to this is selected and read. Such operation is actually a function Fx (T)
(S5).

On the basis of the table Fx that exactly corresponds to the gas type Gx read in this way, the subsequent calculation of the gas flow rate ΔV = Fx (T) to the calculation of the gas integrated flow rate,
The gas flow rate calculation means 104 executes (s6 to 8). That is, first, the gas flow rate ΔV = Fx (T) corresponding to the time T measured at each predetermined time interval is calculated based on the table Fx (s6). Subsequently, the gas flow rate ΔV is integrated to calculate the gas integrated flow rate V (s7). The value of the integrated gas flow rate V thus obtained is displayed on the display means 105 (s8). Alternatively, further, the data of the value of the integrated gas flow rate V is transmitted by the transmitting / receiving means 107 to the data management system (not shown) installed in an external gas company or the like via the transmission path 106 or the like (s9).

As described above, according to the present invention, Ga, G
The gas meter according to the present invention automatically discriminates the gas type Gx regardless of which gas is used among the various types of gas such as b, Gc ... The calculation table Fx of the gas flow rate can be automatically changed (corrected) so that various measurements can be performed.

In this embodiment, the gas fluid data measuring means 101 and the gas flow rate calculating means 104 are
The case where the propagation time T of the ultrasonic wave in the gas is measured and ΔV is calculated based on this is described.
Besides, for example, similar to the above ΔT, the difference between the propagation time in the upstream direction and the propagation time in the downstream direction when the gas is flowing; ΔT is measured, and the gas flow rate ΔV is calculated based on this ΔT. The gas flow rate calculation may be performed by the above method.

Further, in the present embodiment, the case where ΔT = 0, that is, the gas type determining means 102 measures the propagation time t each time the gas flow is stopped has been described. However, a gas meter is installed to measure the propagation time t. It may be done only once at the beginning. That is, a step of adding an ON / OFF switch (not shown) for externally turning on the gas type determination means 102, omitting the means relating to s2, and turning on the ON / OFF switch instead. May be provided, and only when the gas meter 1 is installed in a new installation place, the ON / OFF switch is turned ON and the gas type determination means 102 measures the propagation time t.

Alternatively, when the gas meter is used such that it is continuously used without being replaced until the service life period such as 10 years has passed, and is removed after the service life period has passed, the propagation time is also used. The t may be measured only once at the initial stage when the gas meter is installed. Therefore, in such a case, an initial flag (F = 1 or the like) is set in the CPU 100 of the gas meter 1 at the time of factory shipment, the gas meter 1 is installed and the power is turned on.
The flag (F = 1) is recognized (s1
0). Then, the propagation time t as shown in FIG. 3 above-determination of the gas type Gx-correction of the function Fx (T) (that is, selection of the table Fx) is performed. Then, after the gas type Gx is once determined by setting a flag different from the initial flag (F = 1) such as the flag F = 0 (s11), the gas type Gx is fixedly supported. You may make it use only the said table Fx. That is, after the gas meter 1 is installed and processing such as gas replacement is completed and preparation for use is completed, the installation operator turns on the gas meter.
Then, since F = 1 is recorded in the gas meter 1 at this time, based on this, the determination of Gx is executed as described above (s2 to s11), and thereafter the Gx is fixedly fixed.
The gas flow rate corresponding to x is continued (s6-9). A schematic flow chart in such a case is shown in FIG. Note that in FIG. 5, steps similar to those in FIG. 3 are denoted by the same reference numerals as those in FIG.

(Second Embodiment) In the first embodiment, the so-called ultrasonic measurement method has been described, but the measurement method of the gas fluid data measuring means 101 is not limited to this. Besides this, a turbine flow meter or the like, an example of which is described in the second embodiment, can be used. The schematic configuration of the gas meter of the second embodiment is shown in FIG.

However, in this case, unlike the first embodiment, since the turbine flow meter which is the gas fluid data measuring means 101 does not include the ultrasonic wave transmitter / receivers 303 and 304, the gas type The discrimination means 102 is provided with dedicated ultrasonic wave transmitters / receivers 303 and 304. And the detection of the stop of the gas flow is detected by the turbine flow meter. That is, if the turbine 311 of the turbine flow meter is stopped, the rotary encoder 312 mechanically connected to the turbine 311 is also in a stopped state, and the stop of the gas flow can be detected. Then, the gas meter 2 of the second embodiment
Is a rotary encoder 3 mechanically connected to the turbine 311 such that ΔV = Fx (ω).
It is a function, that is, a table, in which the gas flow rate ΔV is determined corresponding to the rotation speed ω of 12.

Therefore, the gas type discriminating means 102 and the function correcting means 103 can use the same structure and operation as those of the first embodiment, but the function correcting means 10 is used.
The contents of the table itself selected by No. 3 are different from those in the first embodiment, and the contents (data) defining the relationship of ΔV = Fx (ω) with the contents are as described above.
Needless to say, is the table in which is recorded. The other structures and operations are the same as those of the gas meter 1 of the first embodiment.

The gas meter 2 of the second embodiment as described above
Also in the same manner as the gas meter 1 of the first embodiment,
The gas meter according to the present invention automatically determines the gas type Gx regardless of which gas is used among other types of gas such as Ga, Gb, Gc ...
x Automatically changes (corrects) the gas flow rate calculation table Fx so that accurate measurement can be performed optimally for x.
can do.

[0053]

As is clear from the detailed description above, according to the present invention, it is possible to realize a gas meter which can meet various types of required performance with one type of hardware and software structure.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a configuration of a gas meter according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating each unit in the first embodiment as a CPU 100.
It is a figure which shows typically an example at the time of constructing so that it may control centering on.

FIG. 3 is a flowchart showing an outline of an operation of the gas meter of the first embodiment.

FIG. 4 is a graph showing a method of correcting a function Fx.

FIG. 5 is a flowchart showing an outline of an operation in the case of determining the gas type Gx only in the initial stage in the gas meter of the first embodiment.

FIG. 6 is a schematic block diagram of a gas meter according to a second embodiment.
It is a figure which shows typically the case where it builds so that it may control centering on U100.

FIG. 7 is a diagram showing a schematic configuration of a conventional ultrasonic measurement type gas meter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas meter of 1st Embodiment, 2 ... Gas meter of 2nd Embodiment, 101 ... Gas flow rate calculation means, 102 ... Gas type determination means, 103 ... Function correction means, 104 ... Gas flow rate calculation means, 105 ... Display Means, 303, 304 ... Ultrasonic transmitter / receiver

Claims (2)

(57) [Claims] 1. A gas fluid data measuring means for measuring data of a fluid physical quantity of a gas flow, and a fluid of the measured gas flow based on a function for associating the data of the physical quantity with a gas flow rate. In a gas meter of an estimation method having a gas flow rate calculation means for calculating the gas flow rate of the gas from physical quantity data, by propagating ultrasonic waves to the gas during the stop when the flow of the gas is stopped, Gas type discriminating means for discriminating the type of the gas based on the measured data of the propagation time of the ultrasonic wave, and a function for correcting the function so as to match the discriminated gas type. Bei correcting means, based on the corrected functions, and a gas flow rate calculation means for calculating a gas flow rate of the gas from the data of the fluid physical quantity of the measurement gas
The gas type determination means can be switched from the outside.
It is equipped with an ON / OFF switch, and the switch turns on.
Gas to perform the above gas type discrimination only when
A gas meter characterized by being a type discrimination means . 2. The gas meter according to claim 1, wherein the gas fluid data measuring means is arranged so as to face each other with a gas conducting path formed so that a gas flow passes through the cylinder, and Of the gas based on the data of the physical quantity of the propagated ultrasonic wave, and an ultrasonic oscillator and an ultrasonic geophone for detecting the physical quantity of the propagated ultrasonic wave. Is a gas fluid data measuring unit that calculates data of a physical quantity and calculates the gas flow rate based on the data, wherein the gas type determining unit uses the ultrasonic oscillator and the ultrasonic geophone, and is in the stopped state. A gas type discriminating means for discriminating the type of the gas based on the measured data by measuring the propagation time data of the ultrasonic wave by propagating the ultrasonic wave through the gas. Data.