JP3476966B2 - Gas flow meter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas flow meter capable of measuring the gas flow rate of an individual gas device by installing only one gas pipe system in which a plurality of gas devices are used.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, the flow rate of city gas has been measured by installing a gas flow meter 101 on the upstream side of a consumer's gas pipe 14 to measure the gas flow rate consumed by the consumer. The gas consumption is calculated from the measured gas flow rate. On the other hand, for gas consumed in gas equipment used for cooling and heating such as the gas engine heat pump 12, the gas charge is discounted. This is because these gas appliances consume a large amount of money and can be profitable even if they are discounted. Further, the consumption amount of the gas engine heat pump 12, which is a discounted charge, needs to be measured separately from the gas consumption amount consumed by the normal gas equipment 13, and therefore, in addition to the gas flow meter 101 for the normal gas equipment, the gas engine A heat pump dedicated gas flow meter 102 is installed.

[0003]

However, in the conventional gas flowmeter, two gas flowmeters 102 for exclusive use of the gas engine heat pump and a gas flowmeter 101 for normal gas equipment must be installed. As a company, the cost was higher. Further, the gas flow meter is arranged outside the house, but in the urban area, two gas flow meters 101,
It may be difficult to secure a space for mounting the 102. Further, even after the installation, it is difficult to read the gas flowmeters 101 and 102, and it is necessary to read the gas flowmeters at two locations, so that there is a problem that the efficiency of the gas meterreading decreases.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a gas flow meter capable of measuring the gas consumption of individual gas equipment with one gas flow meter. To do.

[0005]

In order to solve the above problems, a gas flow meter of the present invention is a gas flow meter which is attached to a gas pipe to measure the flow rate of gas, and measures the pressure of gas. Pressure sensor, gas pressure fluctuation detection means for detecting the frequency of gas pressure fluctuation of the pressure sensor, and gas pressure fluctuation storing the frequency of gas pressure fluctuation generated by a specific gas device connected to the gas pipe and consuming gas When the gas pressure fluctuation frequency detected by the frequency storage means and the gas pressure fluctuation detection means matches the gas pressure fluctuation frequency stored in the gas pressure fluctuation frequency storage means, the gas of the specific gas equipment is determined from the changed flow rate of the gas. And a gas consumption amount calculation means for calculating the consumption amount.

Further, the gas flow meter of the present invention is, in the gas flow meter described above, a pressure change judging means for judging whether or not the gas pressure fluctuation range is changed from the output of the pressure sensor, and the gas pressure fluctuation detection. A frequency change judging means for judging whether or not the frequency detected by the means has changed, wherein the gas consumption amount calculating means has the frequency detected by the gas pressure fluctuation detecting means as the gas pressure fluctuation frequency. Even if the gas pressure fluctuation frequency stored in the storage means matches, when the pressure change judging means judges that the gas pressure fluctuation width does not change and the frequency change judging means judges that there is no frequency change, it occurs at that time. The changed flow rate of the gas is not used for calculating the gas consumption amount of the specific gas device. Further, the gas flowmeter of the present invention is characterized in that, in the above-mentioned one, the specific gas device is a gas engine heat pump.

[0007]

The gas flow meter of the present invention having the above-mentioned structure is installed in the gas pipe to which a plurality of gas appliances are connected downstream.
The pressure sensor of the gas flow meter measures the pressure of the gas flowing through the gas pipe. Further, the gas pressure fluctuation detecting means detects the frequency of the gas pressure fluctuation based on the gas pressure measured by the pressure sensor. Further, the gas pressure fluctuation frequency storage means stores the frequency of the gas pressure fluctuation in the gas pipe generated by a specific gas appliance connected downstream of the gas pipe and consuming gas. Further, the pressure change determination means determines whether or not the gas pressure fluctuation range has changed based on the output of the pressure sensor. Further, the frequency change determination means determines whether or not the frequency detected by the gas pressure variation detection means has changed.

Further, the gas consumption amount calculating means determines the gas pressure from the current gas flow rate when the frequency detected by the gas pressure fluctuation detecting means matches the gas pressure fluctuation frequency stored in the gas pressure fluctuation frequency storage means. The gas consumption rate is calculated by using the gas flow rate obtained by subtracting the gas flow rate before the fluctuation occurs as the gas consumption flow rate of the specific gas equipment. Here, the gas consumption calculation means is configured such that the pressure change determination means determines the gas pressure fluctuation frequency even if the gas pressure fluctuation frequency detected by the gas pressure fluctuation detection means matches the gas pressure fluctuation frequency stored in the gas pressure fluctuation frequency storage means. When it is determined that the fluctuation range does not change and the frequency change determining means determines that there is no frequency change, the change flow rate of the gas generated at that time is not used for calculating the gas consumption amount of the specific gas equipment.

Explaining in a specific example, when a gas engine heat pump as the specific gas device is connected to a gas pipe, the gas engine heat pump generates a gas pressure fluctuation having a frequency of 10 to 21 Hz in the gas pipe. Has been confirmed by experiments. This 10-21H
The gas pressure fluctuation frequency storage means stores the value of z. Then, the gas pressure fluctuation detecting means has a fluctuation in the gas pressure measured by the pressure sensor, and the fluctuation frequency is 10 to 21H.
When it matches with z, the gas flow rate of the gas engine heat pump is estimated by subtracting the gas flow rate before the frequency is generated from the current gas flow rate, and the gas consumption amount is calculated based on the gas flow rate. . As a result, the gas consumption of a normal gas appliance and the gas consumption of a specific gas appliance such as a gas engine heat pump can be calculated separately, so normal gas appliances are processed at the normal gas rate,
Gas engine heat pumps, etc. can be processed at a discounted gas rate.

[0010]

EXAMPLES A gas flow meter 1 according to an example of the present invention will be described below.
1 will be described in detail with reference to the drawings. FIG. 2 shows a gas piping system using the gas flow meter 11. A gas flow meter 11 is arranged in the flow path of the gas pipe 14. The gas pipe 14 is
It is directly connected to the gas engine heat pump 12 and the normal gas equipment 13. Next, the configuration of the gas flow meter 11 is shown in a block diagram in FIG. A flow rate detection unit 28 that detects the flow rate of passing gas is connected to the CPU 21, which is a control unit. The flow rate detection unit 28 is the same regardless of which of the widely used flow meters such as a membrane flow meter and a fluidic flow meter is used, and therefore detailed description thereof is omitted here.

The CPU 21 has a ROM 22 for storing a control program and a RAM 2 for temporarily storing data and the like.
3, a pressure sensor 20 for measuring the pressure of the gas flowing through the gas flow meter 11, and a display unit 24 for displaying the gas consumption amount are connected. The pressure sensor 20 is connected to the gas pipe 14. Further, in the RAM 23, a gas pressure fluctuation detection program 25 which is a gas pressure fluctuation detection means, a gas pressure fluctuation frequency storage means 26, a gas consumption amount calculation program 27 which is a gas consumption amount calculation means, and a gas pressure from the output of the pressure sensor 20. A pressure change judgment program 29 for calculating a fluctuation range and judging whether or not there is a change in the gas pressure fluctuation range, and a frequency change judgment for judging whether or not there is a change in the frequency obtained by the gas pressure fluctuation detection program 25. The program 30 is stored.

Here, the frequency of the gas fluctuation generated by using the gas engine heat pump 12 can be calculated by the following formula. V = R × S / 60/2 Here, V is the generated gas pressure fluctuation frequency, and the unit is Hz. R is the rotation speed of the gas engine heat pump 12, and the unit is r. p. m. S is the number of cylinders of the gas engine heat pump 12. 60 is the number of seconds per minute, and is divided by 2 because in the case of a 4-cycle engine, the intake valve opens and closes once every two revolutions of the engine.

FIG. 5 shows the generated gas pressure fluctuation frequency calculated based on the data of the gas engine heat pump 12 which is widely used at present. Gas engine heat pump 12
For this, a single-cylinder, 3-hp engine is used. The calculated value is a value calculated from the above formula, and is almost the same as the experimental value measured by the experiment. This value is shown graphically in FIG. The number of revolutions normally used in the gas engine heat pump 12 is 1200 to 2500 rpm. p. m, and the corresponding generated gas pressure fluctuation frequency is 10 to 21 Hz. Therefore, the gas pressure fluctuation frequency storage means 26 stores 10 to 21 Hz as the generated gas pressure fluctuation frequency.

Next, the operation of the gas flow meter 11 having the above structure will be described. FIG. 1 is a flow chart showing the operation of the gas flow meter 11. The gas pressure fluctuation frequency is obtained by Fourier-transforming the gas pressure measured by the pressure sensor 20, and it is determined whether or not it matches the value 10 to 21 Hz which is the value stored in the gas pressure fluctuation frequency storage means 26. Yes (S1). Techniques such as the Fourier transform are well known, and the description thereof is omitted here. The gas pressure fluctuation frequency can be obtained by a simple method other than a complicated mathematical method such as Fourier transform, but it is omitted here. If they match (S1; YES), there is a flow rate change ΔQ, and the pressure change determination program 29 determines that the gas pressure variation width ΔP has changed, or the frequency change determination program 30 determines that the gas pressure variation frequency fp When it is determined that there is a change (S2; YES), it is determined that the flow rate change ΔQ is being consumed by the gas engine heat pump 12, and the flow rate change ΔQ is added as the flow rate QGHP of the gas engine heat pump 12 (S3). Then, QGHP is integrated as the consumption amount of the gas engine heat pump 12 (S4). And S
Return to 1.

When there is no flow rate change ΔQ, or when both the gas pressure fluctuation range ΔP and the gas pressure fluctuation frequency fp have not changed (S2; NO), the conventional QGHP is used as it is. The consumption of the gas engine heat pump 12 is settled (S4). Then, the process returns to S1. In addition, the gas pressure fluctuation frequency is obtained by Fourier-transforming the gas pressure measured by the pressure sensor 20, which is a value stored in the gas pressure fluctuation frequency storage means 26, which is 10 to 21 Hz.
If it does not match (S1; NO), QGHP = 0 is set (S5), and the process returns to S1.

Next, the above-mentioned flow chart will be described with a specific example. FIG. 4 shows changes in the flow rate change ΔQ in time series. The flow rate change ΔQ is a value obtained by subtracting the previously sampled flow rate Q1 from the currently sampled flow rate Q2. In the period shown by a in the figure, the gas engine heat pump 12 is not used and only the normal gas equipment 13 is used. Here, in order to simplify the explanation, it is assumed that the gas consumption amount normally used in the gas equipment 13 is constant. It has been confirmed by experiments that there is almost no gas pressure fluctuation when only the normal gas equipment 13 is used. Therefore, it is confirmed from the output of the pressure sensor 20 that there is no gas pressure fluctuation (S1; NO).
P = 0 (S5), gas engine heat pump 12
Consumption is not added.

Next, in the period b, the case where the gas engine heat pump 12 is operating is shown. Flow rate is Q
Increase from 1 to Q2. Gas engine heat pump 12
When using, gas pressure fluctuations occur in the gas pipe 14. Therefore, it is confirmed that there is a gas pressure fluctuation of 10 to 21 Hz by performing a Fourier transform process on the output of the pressure sensor 20 (S1; YES). And the flow rate is also ΔQ = Q2
Since -Q1 has changed and the gas pressure fluctuation frequency fp has also changed (S2; YES), ΔQ is added to QGHP (S3). Then, the QGHP is integrated as the amount of gas consumed by the gas engine heat pump 12, and RAM2
Store in 3.

Next, a period c shows the case where the gas engine heat pump 12 is stopped. Flow rate is from Q2 to Q
Change to 1. In this case, the gas engine heat pump 1
2 is not used, and only the gas equipment 13 is normally used. Therefore, it is confirmed from the output of the pressure sensor 20 that there is no gas pressure fluctuation (S1; NO).
= 0 (S5), the consumption of the gas engine heat pump 12 is not added. Gas engine heat pump 12
The total gas consumption amount of the normal gas device 13 and the normal gas device 13 is calculated as the total gas consumption amount based on the output of the flow rate detection unit 28, and is stored in the RAM 23. Therefore, from the total gas consumption, the gas engine heat pump 12
The gas consumption of the normal gas appliance 13 can be calculated by subtracting the consumption of. The display unit 24 displays the gas consumption amounts of the gas engine heat pump 12 and the normal gas equipment 13, respectively. By examining each of these, it is possible to charge a gas fee according to each.

Next, a case where the gas consumption of the normal gas equipment 13 changes during the period c will be described. For example, consider a case where a part of the normal gas equipment 13 is stopped and the gas consumption of the normal gas equipment 13 decreases. In this case, since the gas engine heat pump 12 is used, the gas pressure changes in the gas pipe 14. Therefore, the output of the pressure sensor 20 is Fourier-transformed to obtain 10 to 21
It is confirmed that there is a gas pressure fluctuation of Hz (S1; YE
S). And the flow rate is also decreased by ΔQ. However, it is confirmed by the pressure change determination program 29 that the gas pressure fluctuation range ΔP does not change because the operation of the gas engine heat pump 12 has not changed, and the gas pressure fluctuation frequency fp has not changed, either. Is confirmed by the frequency change judgment program 30 (S2; NO), Q
Instead of adding ΔQ to GHP, the previous QGHP is used as it is, accumulated as the gas consumption of the gas engine heat pump 12, and stored in the RAM 23. This allows the normal gas equipment 1 to operate while the gas engine heat pump 12 is operating.
Even if the gas consumption of No. 3 changes, the gas consumption of the gas engine heat pump 12 can be accurately integrated, and the gas consumption of the normal gas equipment 13 can also be accurately integrated.

As described in detail above, according to the gas flow meter 11 of this embodiment, the pressure sensor 20 for measuring the gas pressure and the gas pressure fluctuation detection for detecting the frequency of the gas pressure fluctuation of the pressure sensor 20. The program 25, the gas pressure fluctuation frequency storage means 26 that stores the frequency of the gas pressure fluctuation that is generated by the gas engine heat pump 12 that is connected to the gas pipe and consumes gas, which is 10 to 21 Hz, and the gas pressure fluctuation detection program 25 are detected. The generated gas pressure fluctuation frequency is the gas pressure fluctuation frequency 1 stored in the gas pressure fluctuation frequency storage means 26.
When it matches 0 to 21 Hz, it has a gas consumption amount calculation program 27 for calculating the gas consumption amount of the gas engine heat pump 12 from the gas change flow rate ΔQ, so that one gas flow meter 11 is used. The gas consumption of the gas engine heat pump 12 and the gas consumption of the normal gas equipment 13 can be calculated and displayed individually.

Further, the gas flow meter 11 of this embodiment has a pressure change judging program 29 for judging whether or not the gas pressure fluctuation range has changed from the output of the pressure sensor 20, and the gas detected by the gas pressure fluctuation detecting means. The gas pressure fluctuation frequency storage means 26 has a frequency change judgment program 30 for judging whether or not the pressure fluctuation frequency has changed. Even if it matches the stored gas pressure fluctuation frequency,
When the pressure change judgment program 29 judges that there is no change in the gas pressure fluctuation range and the frequency change judgment program 30 judges that there is no gas pressure fluctuation frequency change, the gas flow rate change ΔQ generated at that time is calculated as the gas engine heat pump 1
2 is not used for calculating the gas consumption amount, the gas consumption of the normal gas device 13 and the gas of the gas engine heat pump 12 are not used even when a part of the normal gas device 13 is stopped during operation of the gas engine heat pump 12. The consumption amount and the consumption amount can be accurately calculated individually.

The above-described embodiments do not limit the present invention at all, and it is needless to say that various modifications and improvements can be made without departing from the scope of the invention. For example, in this embodiment, 10 to 21 Hz is used as the gas pressure fluctuation of the gas engine heat pump 12, but it goes without saying that it may be changed according to the type of the gas engine heat pump 12. Further, it is not limited to the gas engine heat pump 12, and it goes without saying that it can be applied as long as it is a gas device that causes fluctuations in the gas pressure in the gas pipe 14.

[0023]

As is apparent from the above description, according to the gas flow meter of the present invention, the pressure sensor for measuring the gas pressure and the gas pressure fluctuation detecting means for detecting the frequency of the gas pressure fluctuation of the pressure sensor. And a gas pressure fluctuation frequency storage means for storing the frequency of the gas pressure fluctuation generated by a specific gas device connected to the gas pipe and consuming gas, and the gas pressure fluctuation frequency detected by the gas pressure fluctuation detection means is the gas pressure fluctuation. Since the frequency storage means has a gas consumption amount calculation means for calculating the gas consumption amount of the specific gas equipment from the changed flow rate of the gas when the gas pressure fluctuation frequency is stored, one gas flow meter is provided. Using, the gas consumption of the specific gas equipment and the gas consumption of the normal gas equipment can be calculated and displayed individually.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation of a gas flow meter 11 which is an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a gas piping system in which a gas flow meter 11 is used.

FIG. 3 is a block diagram showing a configuration of control means of the gas flow meter 11.

FIG. 4 is a data diagram showing changes in gas flow rate Q.

FIG. 5 is a first data diagram showing a relationship between the gas engine heat pump 12 and a gas pressure fluctuation.

FIG. 6 is a second data diagram showing the relationship between the gas engine heat pump 12 and the gas pressure fluctuation.

FIG. 7 is a block diagram showing a configuration of a gas piping system in which a conventional gas flow meter is used.

[Explanation of symbols]

11 gas flow meter 12 gas engine heat pump 13 Normal gas equipment 20 Pressure sensor 25 Gas pressure fluctuation detection program 26 gas pressure fluctuation frequency storage means 27 Gas consumption calculation program 28 Flow rate detector 29 Pressure change judgment program 30 Frequency change judgment program

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takato Sato 507-2 Shintakaracho, Tokai City, Aichi Toho Gas Co., Ltd., Research Institute (56) Reference JP-A-7-151579 (JP, A) JP 5-107096 (JP, A) JP-A-5-215585 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 1/00-9/02

Claims (3)

(57) [Claims] 1. A gas flow meter attached to a gas pipe for measuring the flow rate of gas, comprising: a pressure sensor for measuring the pressure of the gas; and a gas pressure fluctuation detecting means for detecting the frequency of the gas pressure fluctuation of the pressure sensor. And a gas pressure fluctuation frequency storage means for storing a frequency of gas pressure fluctuation generated by a specific gas device connected to the gas pipe and consuming gas, and the frequency detected by the gas pressure fluctuation detection means is the gas A gas consumption amount calculating unit for calculating a gas consumption amount of the specific gas equipment from a gas change flow rate when the gas pressure fluctuation frequency stored in the pressure fluctuation frequency storage unit matches. Flowmeter. 2. The pressure change means for determining whether or not the gas pressure fluctuation range has changed from the output of the pressure sensor, and the frequency detected by the gas pressure fluctuation detection means according to claim 1. A frequency change determination means for determining whether or not the gas pressure fluctuation frequency storage means stores the gas pressure stored in the gas pressure fluctuation frequency storage means. Even when the frequency variation coincides with the variation frequency, when the pressure variation determining means determines that the pressure variation width does not change, and the frequency variation determining means determines that there is no frequency variation, the variation flow rate of the gas generated at that time is A gas flow meter that is not used to calculate the gas consumption of a specific gas appliance. 3. The gas flowmeter according to claim 1, wherein the specific gas device is a gas engine heat pump.