JP2001296166A - Flow rate measurement method, flow rate-measuring device, and electronic gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate-measuring device for reducing the power consumption, without reducing flow rate measurement accuracy by reducing wasteful consumption of power. SOLUTION: A passage flow rate measurement means 5a-1 can be operated in either measurement mode, that is selected out of a first measurement mode for measuring passage flow rate, based on physical quantity by measuring the physical quantity that changes according to the flow velocity of gas in a gas channel at every second prescribed time that is shorter than the first prescribed time, and a second measurement mode for measuring the passage flow rate based on the average value of the physical quantity which is measured plural number of times by intermittently measuring the physical quantity at every second prescribed time plural times. A measurement mode selection means 5a-3 selects the first and second measurement modes, when it detects the absence of a pulsating current by a pulsating current detection means 5a-2 and the presence of a pulsating current, respectively, thus enabling passage flow rate measurement means 5a-1 to measure the passage flow rate by the selected measurement mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow measuring device and an electronic gas meter, and more particularly to a flow measuring method and a flow measuring device for measuring a flow rate of a fluid such as a gas, and a flow measuring device for measuring a flow rate of a gas measured by the device. The present invention relates to an electronic gas meter for integrating and displaying.

[0002]

2. Description of the Related Art Conventionally, as this type of flow measuring device, there is a thermal flow measuring device using a thermal sensor. The thermal type flow rate measuring device comprises a flow rate sensor including a heater for heating the inside of the gas flow path and temperature sensors provided respectively in the upstream and downstream directions of the gas flow path, and transmits the heat generated by the heater in the upstream and downstream directions. Changes depending on the magnitude of the flow velocity,
The flow velocity is indirectly measured by a physical quantity consisting of a temperature difference intermittently detected by a temperature sensor provided upstream and downstream of the heater.

[0003]

Some combustors that consume gas supplied through an electronic gas meter cause pressure fluctuations in the supplied gas pressure during use. For example, in the case of a GHP (gas heat pump), the use thereof causes a variation of about 50 mmH ₂ O in the gas pressure by 10%.
It occurs at a frequency of 〜20 Hz. Such a GHP is a pulsating flow source that generates a pulsating flow in the gas flow path, and when installed and used in a specific consuming house in an apartment house or the like, an electronic gas meter of a neighboring house is generated due to pressure fluctuations caused by the GHP. Since an instantaneous gas flow occurs in the gas flow path inside, a time difference corresponding to a certain flow rate is measured. If this is mistaken for the gas flow rate accompanying gas consumption and the integrated flow rate is calculated as the passing flow rate, the integrated value will be larger than the actual gas consumption, which is fatal for a measuring instrument. This is a reliability issue.

[0004] That is, when a pressure fluctuation occurs in the electronic gas meter as shown in FIG. 11A in a state where no gas is consumed, the gas in the gas flow path is moved upstream and downstream due to the influence of the pressure fluctuation. 11B, pulsation of 10 to 20 Hz occurs as shown in FIG. If the intermittent measurement is performed in response to this, the passing flow rate as shown in FIG. 11C is obtained, and the measurement is performed at the timing A even when the gas is not used at all. The passing flow rate Ta is accumulated.

Further, when the above-mentioned pressure fluctuation occurs on the upstream side of the electronic gas meter of a consumer house consuming gas, the flow rate in the gas flow path of the consumer house repeatedly increases and decreases. When an electronic gas meter is used to determine a passing flow rate that repeats such an increase and decrease, as in recent years, a gas leak detection function and a security function such as a gas leak alarm function and a gas supply cut-off function linked to the gas leak detection function are electronically operated. When mounted on a gas meter, the following problems occur.

That is, although the gas flow rate does not actually exceed the gas leakage determination level, the flow rate exceeding the gas leakage determination level is obtained by the electronic gas meter from the relationship of the measurement timing, and the gas leakage warning and supply gas are obtained. Even if the cut-off is performed erroneously, or conversely, despite the fact that it actually exceeds the gas leak determination level, the passage flow rate below the gas leak determination level is determined by the electronic gas meter from the relationship of the measurement timing, A problem arises in that the execution of the gas leak alarm and the supply cutoff is delayed.

Therefore, there are the following electronic gas meters incorporating a flow rate measuring device for solving the above-mentioned problems. That is, as shown in FIG. 5 (b1), at every first predetermined time T2, the physical quantity corresponding to the flow velocity is intermittently measured n1 times, and the average value of the physical quantity measured n1 times and the cross-sectional area of the gas flow path are obtained. The flow rate of the gas in the gas passage is measured by multiplying the gas flow by the second predetermined time T2. As described above, by taking the average value of the gas flow rate measured n1 times, even if the gas flow rate fluctuates due to the pulsating flow, the increase / decrease is canceled out, and an accurate passing flow rate can be measured.

The period of the pulsating flow is 50 msec to 100 msec.
The intermittent interval T4 is half of 50 msec to reliably cancel the flow rate fluctuation due to the pulsating flow.
Must be set to msec or less. As described above, by setting the intermittent interval T4 to be equal to or less than half of the minimum pulsating flow period 50 msec, for example, the vicinity of the maximum value of the pulsating flow, that is, the peak portion of the pulsating flow is repeatedly sampled, Does not become larger than the passing flow rate, or the vicinity of the minimum value of the pulsating flow, that is, the valley portion of the pulsating flow is repeatedly sampled, and even if the average value is obtained, the obtained passing flow rate does not become smaller than the actual passing flow rate.

In the electronic gas meter that takes the above-mentioned average value, when the flow rate is measured in a gas flow path in which a pulsating flow is generated, the flow rate measurement accuracy is improved as compared with the above-described conventional case. However, if you take the average when there is no pulsation,
Although the flow measurement accuracy is almost the same as the conventional one described above,
In the related art, the passage flow rate can be obtained by one measurement. However, since the passage flow rate cannot be obtained unless measurement is performed several times, a large amount of power is consumed as compared with the above-described related art. That is, there is a problem in that useless measurement of a physical quantity that does not lead to improvement in flow rate measurement accuracy causes useless power consumption.

Accordingly, the present invention focuses on the above problems, and reduces the power consumption by reducing wasteful power consumption without lowering the flow measurement accuracy. It is an object to provide a flow measurement device.

The present invention also provides an electronic gas meter capable of reducing the useless power consumption, thereby reducing the error in the passing flow rate and accurately integrating and displaying the gas usage even if the power consumption is reduced. The task is to provide

[0012]

According to a first aspect of the present invention, there is provided a method for detecting the presence or absence of a pulsating flow, which is a flow fluctuation, at every first predetermined time, and detecting the absence of a pulsating flow. Then, a physical quantity that changes according to the flow velocity of the gas in the gas flow path is measured at every second predetermined time shorter than the first predetermined time, and the passing flow rate is measured based on the measured physical quantity, A flow rate measuring method comprising: intermittently measuring the physical quantity a plurality of times every second predetermined time when detecting the presence; and measuring a passing flow rate based on an average value of the physical quantities measured a plurality of times. Exist.

According to the first aspect of the present invention, when the absence of the pulsating flow is detected, a physical quantity corresponding to the flow velocity is measured at every second predetermined time, and the passing flow rate is measured based on the measured physical quantity. When the presence of the pulsating flow is detected, the physical quantity is intermittently measured a plurality of times at every second predetermined time, and the passing flow rate is measured based on the average value of the physical quantities measured a plurality of times. By the way, the second
Since the passing flow rate measurement based on the average value of the physical quantity intermittently measured a plurality of times every predetermined time increases the number of times of measurement, the power consumption is larger than when the physical quantity is simply measured every second predetermined time. Become. However, by taking an average value of the physical quantities measured a plurality of times, when there is a pulsating flow, the fluctuation can be canceled out, and it is effective to obtain the passing flow rate with the pulsating flow.
Further, when there is no pulsating flow, it is not necessary to cancel out the fluctuation, so that simply measuring the passing flow rate based on the physical quantity measured every second predetermined time does not reduce the flow rate measurement accuracy.

Therefore, when the presence of a pulsating flow is detected, the second
If the physical quantity is intermittently measured a plurality of times every predetermined time, and the passing flow rate is measured based on the average value of the physical quantities measured a plurality of times, even if a pulsating flow occurs, the flow rate measurement accuracy decreases. There is no. When no pulsation is detected, the second
If a physical quantity corresponding to the flow velocity is measured every predetermined time and the passing flow rate is measured based on the measured physical quantity, the passing flow rate is not calculated by consuming a large amount of electric power despite the absence of a pulsating flow. , The instantaneous flow rate can be accurately measured, so that unnecessary power is not consumed.

According to a second aspect of the present invention, there is provided a pulsating flow detecting means for detecting the presence or absence of a pulsating flow, which is a flow fluctuation at every first predetermined time, and a pulsating flow detecting means for changing the pulsating flow in accordance with a gas flow rate in the gas flow path. A first measurement mode in which a physical quantity to be measured is measured at every second predetermined time shorter than the first predetermined time, and a passing flow rate is measured based on the measured physical quantity, and the physical quantity is measured at every second predetermined time. A passing flow rate measuring means 5a-1 operable in one selected measuring mode among the second measuring modes of intermittently measuring a plurality of times and measuring the passing flow rate based on an average value of the physical quantities measured a plurality of times. Selecting the first measurement mode when no pulsation is detected by the pulsation flow detection means, and selecting the second measurement mode when detecting the presence of the pulsation flow, and allowing the passing flow rate measurement means to pass through the selected measurement mode. Measurement mode for measuring the flow rate Lies in the flow rate measuring apparatus characterized by comprising a selection means 5a-3.

According to the second aspect of the present invention, the pulsating flow detecting means 5a-2 detects the presence or absence of a pulsating flow, which is a flow fluctuation, at every first predetermined time. The passing flow rate measuring unit 5a-1 measures a physical quantity that changes according to the flow velocity of the gas in the gas flow path at every second predetermined time shorter than the first predetermined time, and determines the passing flow rate based on the measured physical quantity. Among the first measurement mode for measuring and the second measurement mode for intermittently measuring the physical quantity a plurality of times every second predetermined time and measuring the passing flow rate based on the average value of the physical quantities measured a plurality of times, It can operate in one of the selected measurement modes. Measurement mode selection means 5
a-3 selects the first measurement mode when the pulsating flow detecting means 5a-2 detects the absence of the pulsating flow, and selects the second measuring mode when detecting the presence of the pulsating flow.
1 allows the measurement of the passing flow rate in the selected measurement mode.

Incidentally, the measurement of the passing flow rate in the second measurement mode requires measuring the physical quantity a plurality of times. Therefore, the measurement of the passing flow rate based on the physical quantity obtained by one measurement is compared with the first measurement mode. Although the power consumption increases, the average value of the physical quantities measured a plurality of times can be used to offset the fluctuation when there is a pulsating flow, which is effective for obtaining the passing flow rate having the pulsating flow. Further, when there is no pulsating flow, it is not necessary to cancel the fluctuation, so that even if the passing flow rate is measured in the first measurement mode with low power consumption, the flow rate measurement accuracy does not decrease.

Therefore, the presence or absence of a pulsating flow is detected by the pulsating flow detecting means 5a-2 at every first predetermined time, and when the presence of the pulsating flow is detected, the measuring mode selecting means 5a-3 switches the second measuring mode. If set, even if a pulsating flow occurs, the flow measurement accuracy does not decrease. Also, the pulsating flow detecting means 5a
If the measurement mode selection means 5a-3 sets the first measurement mode when the absence of pulsation is detected by -2, even if there is no pulsation, more power is consumed in the second measurement mode. Since the passing flow rate is no longer required and the instantaneous flow rate can be accurately measured while suppressing power in the first measurement mode, unnecessary power is not consumed.

According to a third aspect of the present invention, the interval between the intermittent physical quantity measurements in the second measurement mode is set to be less than the cycle of the pulsating flow. Exists in measuring equipment.

According to the third aspect of the present invention, the interval of the intermittent physical quantity measurement in the second measurement mode is set to be less than the cycle of the pulsating flow. Since the peaks and valleys of the flow fluctuation due to the flow can be measured, the fluctuation of the flow can be canceled by averaging.

According to a fourth aspect of the present invention, the pulsating flow detecting means detects the presence or absence of a pulsating flow based on physical quantities measured a plurality of times at intervals shorter than the minimum value of the period of the pulsating flow. A flow rate measuring device according to claim 2 or 3 is provided.

According to the fourth aspect of the present invention, the pulsating flow detecting means 5a-2 detects the presence or absence of a pulsating flow based on physical quantities measured a plurality of times at intervals shorter than the minimum value of the fluctuation period of the pulsating flow. If the physical quantity is measured, there is no need to provide any separate means for detecting the presence or absence of a pulsating flow.

According to a fifth aspect of the present invention, when the pulsating flow detecting means detects the presence of a pulsating flow, the pulsating flow period is measured based on physical quantities measured a plurality of times by the pulsating flow detecting means. Measuring means 5a-4, and further comprising intermittent interval setting means 5a-5 for resetting the interval of the intermittent physical quantity measurement in the second measurement mode based on the cycle measured by the pulsating cycle measuring means. The flow rate measuring device according to any one of claims 2 to 4, wherein

According to the fifth aspect of the present invention, when the pulsating cycle measuring means 5a-4 detects the presence of a pulsating flow from the pulsating flow detecting means 5a-2, the pulsating flow detecting means 5a-2 measures a plurality of times. The cycle of the pulsating flow is measured based on the physical quantity, and the intermittent interval setting means 5a-5 sets the interval of the intermittent physical quantity measurement in the second measurement mode based on the cycle measured by the pulsating cycle measuring means 5a-4. Since the physical quantity can be measured at every intermittent interval according to the cycle of the pulsating flow, the measurement is performed with a fine intermittent time in accordance with the pulsating flow with a short cycle despite the occurrence of the pulsating flow with a relatively long cycle And no wasteful power is consumed. Moreover, the pulsating cycle measuring means 5
Since a-4 measures the cycle of the pulsating flow based on the physical quantity measured a plurality of times by the pulsating flow detecting means 5a-2, there is no need to provide any additional means for detecting the cycle of the pulsating flow.

According to a sixth aspect of the present invention, the pulsating cycle measuring means detects the presence of a pulsating flow by the pulsating flow detecting means only during a learning period provided at every third predetermined time longer than the first predetermined time. The intermittent interval setting means measures the cycle of the pulsating flow at the time of detection, and resets the intermittent physical quantity measuring interval based on the cycle measured by the pulsating cycle measuring means during the learning period. The flow rate measuring device according to claim 5, characterized in that:

According to the sixth aspect of the present invention, the pulsating flow detecting means 5 is provided only during the learning period provided by the pulsating cycle measuring means 5a-4 at every third predetermined time longer than the first predetermined time.
The intermittent interval setting means 5a-5 measures the cycle of the pulsating flow when the presence of pulsating flow is detected by a-2, and the intermittent interval setting means 5a-5 intermittently operates based on the cycle measured by the pulsating cycle measuring means 5a-4 during the learning period. Reset the interval of physical quantity measurement. Therefore, the second measurement mode is performed in accordance with the intermittent flow rate measurement interval set by the intermittent interval setting means 5a-5 based on the pulsation cycle measured by the pulsation cycle measurement means 5a-4 during the learning period. Accordingly, it is not necessary to determine the cycle every time the presence of the pulsating flow is detected during periods other than the learning period, and the power consumption required for determining the cycle can be reduced. Further, even if the usage mode of the burning appliance changes depending on the season, the learning period is provided at every third predetermined time, so that the intermittent physical quantity measurement can be performed based on the cycle of the pulsating flow that changes according to the usage mode. You can reset the interval.

According to a seventh aspect of the present invention, at each timing synchronized with the pulsating flow detecting means, a swell detecting means for detecting the presence or absence of swelling, which is a flow fluctuation of a cycle longer than the pulsating flow.
a-6, wherein the passing flow rate measuring means can further select a third measurement mode for measuring a passing flow rate based on an average value of physical quantities measured a plurality of times every the second predetermined time, The flow measurement device according to any one of claims 2 to 6, wherein the measurement mode selection means selects the third measurement mode when the presence of undulation is detected by the undulation detection means.

According to the seventh aspect of the present invention, the swell detecting means 5a-6 detects the presence or absence of swell, which is a flow fluctuation of a longer cycle than the pulsating flow, at each timing synchronized with the pulsating flow detecting means 5a-2, When the measurement mode selection means 5a-3 detects the presence of the swell by the swell detection means 5a-6, a third measurement mode for measuring the passing flow rate based on the average value of the physical quantity measured a plurality of times at the second predetermined time is selected. I do.

As a result of the flow rate of the gas being adjusted by passing through the bent pipe, swelling, which is a flow rate fluctuation with a period larger than the pulsating flow generated by the gas heat pump, may occur. Therefore, when the swell detecting means 5a-6 detects the presence of the swell, the variation due to the swell can be canceled by taking the average value of the physical quantities measured a plurality of times at every second predetermined time.

The invention according to claim 8 is characterized in that the second predetermined time in the third measurement mode is set to be less than the cycle of the swell. Exist.

According to the eighth aspect of the present invention, since the second predetermined time in the third measurement mode is set to be shorter than the cycle of the swell, a plurality of measurements for each second predetermined time are performed. Since the peak portion and the valley portion of the flow fluctuation due to the undulation can be measured, the fluctuation of the flow can be canceled by averaging.

According to a ninth aspect of the present invention, the undulation detecting means detects the presence or absence of undulation based on a moving average of physical quantities measured a plurality of times at intervals shorter than the minimum value of the pulsating cycle. The flow rate measuring device according to claim 7 or claim 8.

According to the ninth aspect of the present invention, whether or not the swell has occurred based on the moving average value of the physical quantity measured a plurality of times by the swell detecting means 5a-6 at intervals shorter than the minimum value of the period of the pulsating flow. Is determined, the presence or absence of the swell can be detected by measuring the physical quantity, so that there is no need to provide any separate means for detecting the presence or absence of the swell.

According to a tenth aspect of the present invention, when the presence of undulation is detected by the undulation detecting means, the undulation period measuring means measures the undulation cycle based on the moving average of the physical quantity measured a plurality of times by the undulation detecting means. 5a-7
And a second predetermined time setting means (5a-8) for resetting the second predetermined time based on a cycle measured by the undulation cycle measuring means.
The present invention resides in any one of the flow rate measuring devices described above.

According to the tenth aspect, when the swell period measuring means 5a-7 detects the presence of the swell by the swell detection means 5a-6, the moving average of the physical quantity measured by the swell detection means 5a-6 a plurality of times. The swell period is measured based on the value, and the second predetermined time setting means 5a-8 sets the second swell cycle based on the cycle measured by the swell cycle measurement means 5a-7.
Since the predetermined time is reset, the physical quantity can be measured at every second predetermined time according to the cycle of the undulation. The measurement is not performed in the second predetermined time, and no wasteful power is consumed. Moreover,
The swell period measuring means 5a-7 is replaced by the swell detection means 5a-6.
Since the undulation cycle is measured based on the physical quantity measured a plurality of times, there is no need to provide any additional means for detecting the undulation cycle.

According to an eleventh aspect of the present invention, the swell period measuring means detects the presence of the swell by the swell detection means only during a learning period provided at every third predetermined time longer than the first predetermined time. The swell cycle is measured, and the second predetermined time setting means resets the second predetermined time based on a cycle measured by the swell cycle measurement means during a learning period. 10 is a flow rate measuring device.

According to the eleventh aspect of the present invention, the undulation is provided by the undulation detecting means 5a-6 only in the learning period provided by the swell period measuring means 5a-7 at every third predetermined time longer than the first predetermined time. The swell cycle when the presence is detected is measured, and the second predetermined time setting means 5a-8 sets a second predetermined time based on the cycle measured by the swell cycle measurement means 5a-7 during the learning period. cure. Therefore, the second predetermined time setting means 5a-8 based on the swell cycle measured by the swell cycle measuring means 5a-7 during the learning period.
Performs the third measurement mode in accordance with the second predetermined time set by the user, it is not necessary to calculate the cycle every time the presence of the swell is detected during the period other than the learning period, and the power consumption required to determine the cycle is reduced. be able to. In addition, even if the usage mode of the burning appliance changes depending on the season, the learning period is provided every third predetermined time period, so that the second predetermined time period is set based on the swell cycle that changes according to the usage mode. You can do it again.

According to a twelfth aspect of the present invention, there is provided a detection stop means SW for stopping detection of the presence or absence of a pulsating flow by the pulsating flow detecting means.
The flow rate measuring device according to any one of claims 2 to 11, further comprising:

According to the twelfth aspect, the detection stopping means SW1 stops the detection of the presence or absence of the pulsating flow by the pulsating flow detecting means 5a-2. When it is known in advance that the pulsating flow is installed, the detection stop means SW1 stops detecting the pulsating flow, so that the power consumption associated with the pulsating flow detection can be reduced.

According to a thirteenth aspect of the present invention, the detection stopping means stops the detection of the presence or absence of the pulsating flow by the pulsating flow detecting means in response to a detection stopping signal transmitted from the outside via a communication line. A flow rate measuring device according to claim 12 characterized by the above-mentioned.

According to the thirteenth aspect of the present invention, the detection of the presence or absence of the pulsating flow by the pulsating flow detecting means 5a-2 is stopped in response to the detection stopping signal transmitted from the outside via the communication line. Therefore, the detection of the pulsating flow by the pulsating flow detecting means 5a-2 can be stopped by a remote operation from the inside of the gas company or the management company which grasps the usage state of the gas heat pump, that is, from the outside.

The invention according to claim 14 is the invention according to claims 2 to 13
Any one of the flow rate measuring device, the flow rate integrating means 5a-9 for integrating the passing flow rate of the gas measured in the measurement mode selected by the measuring mode selecting means, and the passing flow rate integrated by the flow rate integrating means. The electronic gas meter is provided with a display means 7 for displaying.

According to a fourteenth aspect of the present invention, the flow rate integrating means 5a-9 integrates the gas flow rate measured by the passing flow rate measuring means 5a-1 provided in the flow rate measuring device according to any one of the second to thirteenth aspects. , Display means 7 is flow rate integrating means 5a-
Since the integrated flow rate is displayed by 9, the accurate passing flow rate measured by the flow rate measuring device capable of further reducing power consumption can be integrated and displayed without lowering the flow rate measurement accuracy.

[0044]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an electronic gas meter incorporating a flow rate measuring device implementing the flow rate measuring method of the present invention. The illustrated electronic gas meter is configured as a thermal type, and is provided in a gas flow path as a flow path in a gas meter for flowing a gas as a fluid, and includes a micro flow sensor 1 that outputs a signal corresponding to a gas flow rate. Have.

As shown in FIG. 3, the micro flow sensor 1 is disposed on an inner wall of a gas flow path 10 shown in a cross section in FIG. 3, and has a semiconductor base 11 and a semiconductor base 11 formed on the semiconductor base 11. A thin film layer (not shown), temperature sensors 12 and 13 such as a thermopile for generating a thermoelectromotive force according to the temperature formed on the thin film layer, and a heater resistor 14 for heating. The temperature sensor 12, the heater resistor 14, and the temperature sensor 13 are arranged at regular intervals along the flow direction D in this order from the upstream side in the flow direction D of the gas flowing in the flow path 10.

The above-described heater resistor 14 is connected to the power supply 3 via the switch 2 as shown in FIG.
The power supply 3 has a battery 31 and a constant voltage circuit 33 as shown in FIG. 4, and is configured to output the voltage of the electric power from the battery 31 as a predetermined constant voltage by the constant voltage circuit 33. Microcomputer (hereinafter,
Turns on in response to the output of the control signal S1 from the μCOM) 5, and applies a predetermined constant voltage from the power supply 3 to the heater resistor 14. That is, the heater resistor 14 is energized and heated by the drive pulse output in response to the control signal S1 from the μCOM5. Further, when thermopiles are used as the temperature sensors 12 and 13, the thermo-electromotive forces respectively become non-inverting amplifier circuits 15 and 1 as shown in the equivalent circuit diagram in FIG.
After the signal is non-inverted through 6, the differential amplifier 17 outputs a signal corresponding to the difference therebetween.

The principle of the micro flow sensor 1 having the above configuration will be described below. The heater resistor 14 has a μC
Electricity is applied by a drive pulse simultaneously with the output of the control signal S1 from the OM 5, and heating is performed for a predetermined time. As a result,
When no gas flows through the gas flow path 10, heat is transmitted to the gas near the heater resistor 14, and the upstream and downstream temperature distribution near the heater resistor 14 has a symmetrical distribution. That is, since the temperatures of the temperature sensors 12 and 13 rise to the same temperature, the thermoelectromotive forces of the temperature sensors 12 and 13 become almost equal, and the output from the differential amplifier 17 becomes almost zero.

Now, while the heater resistor 14 is energized,
When the gas flows in the gas flow direction D in FIG. 3, the upstream side is cooled and the temperature drops. On the other hand, on the downstream side, the heat conduction is promoted from the heater resistor 14 by using the gas flow as a medium, and the temperature rises. As a result, the temperature of the temperature sensor 12 on the upstream side of the heater resistor 14 is decreased by the gas, so that the thermoelectromotive force is reduced. On the other hand, the temperature of the temperature sensor 13 on the downstream side is increased by the gas, so that the thermoelectromotive force is increased. I do. When the flow velocity increases, the above-mentioned temperature drop and temperature rise also increase, so that the temperature sensor 1
The output from the differential amplifier 17, which is the difference between the thermoelectromotive forces 2 and 13, is an output corresponding to the flow velocity. Then, the signal from the differential amplifier 17 of the micro flow sensor 1 corresponding to the gas flow rate is amplified by the amplifier 6 and then supplied to the μCOM 5.

The above-mentioned μCOM 5 includes a central processing unit (CPU) 5a for performing various processes according to a program,
ROM 5b, which is a read-only memory storing a program for processing performed by the CPU 5a, a work area used in various processing steps in the CPU 5a, and a RAM 5c, which is a read / write memory having a data storage area for storing various data. And an A / D converter 5d for sampling an analog amplified signal corresponding to the flow velocity of the gas flowing in the gas flow path 10 in which the signal from the micro flow sensor 1 is amplified by the amplifier 6 and converting the amplified signal into a digital value. These are interconnected by a bus line (not shown).

The CPU 5a in the .mu.COM 5 intermittently outputs the control signal S1 to energize the heater resistor 14 with a drive pulse, and supplies the A / D converter 5d with an amplifier 6 corresponding to the flow velocity of the gas output by energization. A sampling process is performed to measure a physical quantity that changes in accordance with the gas flow rate by sampling an analog amplified signal from the microcomputer and converting the amplified signal into a digital value.

Further, the CPU 5a in the μCOM 5
A pulsating flow detection process for detecting the presence or absence of a pulsating flow, which is a flow rate variation generated by driving a GHP or the like at every predetermined time (hereinafter, a predetermined time T1), and a pipe bent at a timing synchronized with the pulsating flow detecting process. Swell detection processing for detecting the presence or absence of swell, which is a flow fluctuation with a longer cycle than the pulsation flow generated as a result of the gas flow rate being adjusted by passing through the slag, and pulsation detection processing and swell detection among the three measurement modes Any one of them is selected according to the detection result of the processing, and the measurement mode selection processing for measuring the passing flow rate in the selected measurement mode is performed. That is, the CPU 5a functions as a pulsating flow detecting unit, a swell detecting unit, and a measurement mode selecting unit.

The three measurement modes will be described below with reference to the timing chart of the measurement processing shown in FIG. Note that X indicates the timing of sampling by the A / D converter 5d in the μCOM 5. As shown in the figure, the digital value of the sampled amplified signal and the gas flow path 1 are obtained by executing the measurement processing of the CPU 5a at every second predetermined time T2 (hereinafter, predetermined time T2) shorter than the predetermined time T1.
A first measurement mode (FIG. 5 (a1)) in which the cross-sectional area of zero is multiplied by a predetermined time T2 to measure the flow rate of the gas flowing during the predetermined time T2 (FIG. 5 (a1)). A second measurement mode for measuring the flow rate of gas flowing during the predetermined time T2 by multiplying the digital value of the amplified signal, the cross-sectional area of the gas flow path 10, and the predetermined time T2 (FIG. 5 (b1)) And a predetermined time T2
A third measurement mode (FIG. 5 (c1)) in which the digital value of the amplified signal sampled n2 times, the sampling number n3, and the predetermined time T2 are multiplied to measure the flow rate of the gas flowing during the predetermined time T2 * n3. ).

That is, in the measurement of the flow rate in the second measurement mode, the flow rate of the gas flowing during the predetermined time T2 is measured only after sampling the amplified signal n1 times. On the other hand, in the measurement of the passing flow rate in the first measurement mode, the passing flow rate of the gas flowing during the predetermined time T2 is obtained based on the digital value of the amplified signal in one sampling. As shown in a2) and (b2),
In the measurement of the passing flow rate in the second measurement mode as compared with the first measurement mode, the energization time of the heater resistor 14 becomes longer,
As a result, power consumption increases. However, due to the pulsating flow generated by driving the GHP, 5
When a flow rate variation of 0 msec to 100 msec occurs, the variation can be canceled by taking the average value of the digital values of the amplified signals sampled n1 times at the intermittent interval T4. This is effective for obtaining the flow rate of 10 passages. Further, when the pulsating flow is not generated, it is not necessary to cancel the fluctuation due to the pulsating flow, so that even if the passing flow rate is measured in the first measurement mode with low power consumption, the flow rate measuring accuracy does not decrease.

Therefore, in the measurement mode selection process of the CPU 5a, the first measurement mode is selected when no pulsation is detected by the pulsation detection process, and the second measurement mode is selected when pulsation is detected. And set. By the measurement mode selection process, the second measurement mode does not consume more power than necessary to determine the passing flow rate even though the gas flow rate does not fluctuate due to the pulsating flow. , And the passing flow rate can be accurately measured, so that unnecessary power is not consumed.

Further, as a result of the gas flow rate being adjusted by passing through the meandering pipe, as described above, the pulsating flow generated by driving the GHP has a larger flow rate fluctuation of about 1 s to 60 s. May occur. It is necessary to average the digital values of the sampled amplified signals in order to cancel the flow fluctuation caused by the undulation. Therefore, in the measurement mode selection process of the CPU 5a, when the presence of swell is detected by the swell detection process, the third measurement mode is selected and the predetermined time T2 is set.
By taking the average value of the digital values of the amplified signal sampled n2 times every time, the fluctuation due to the undulation can be canceled out, and the flow rate measurement accuracy can be further improved.

The flow rate fluctuation such as the pulsating flow and the swell can be obtained by sampling the amplified signal corresponding to the peak portion and the valley portion of the flow rate change by performing a measurement process less than the fluctuation period. Taking a value can surely offset the fluctuation. Therefore, the cycle of the pulsating flow generated by driving the GHP is about 50 msec to 100 msec,
Since it is known in advance that the cycle of the swell resulting from the gas flow rate being adjusted by passing through the curved pipe is about 1 s to 60 s, the intermittent interval T4 is the minimum value of the cycle of the pulsating flow. The predetermined time T2 is set in advance to a value less than 50 msec and a value less than 1 s, which is the minimum value of the swell period.

When detecting the presence of a pulsating flow in the pulsating flow detecting process, the CPU 5a in the μCOM 5 sets a pulsating cycle measuring process for measuring the period of the pulsating flow and a period measured by the pulsating cycle measuring process. An intermittent interval setting process for resetting the intermittent time T4 based on the swell period detected by the swell detection process, a swell period measurement process for measuring the swell period, and a predetermined time based on the cycle measured by the swell period measurement process. A second predetermined time setting process for resetting T2 is performed. That is, the CPU 5a functions as a pulsating cycle measuring unit, an intermittent interval setting unit, a swell cycle detecting unit, and a second predetermined time setting unit.

As described above, by making the intermittent interval T4 variable by the intermittent interval setting process, a pulse having a relatively long period, for example, 100 msec, but having a short period, for example, 50 msec. Since the measurement is not performed at the adjusted fine intermittent interval T4, for example, T4 = 50 msec / 2, the intermittent interval T4 corresponding to the pulsating flow having a long cycle of 100 msec, that is, T4 = 100 msec / 2, can be reset. The power consumption can be reduced without consuming a large amount of power and without further lowering the flow rate measurement accuracy. Similarly, in the second predetermined time setting process, the predetermined time T2 according to the swell cycle can be reset, so that unnecessary power is not consumed and the flow rate measurement accuracy is further reduced. Without inviting, power consumption can be reduced.

Now, details of the above-described pulsation flow determination processing, swell determination processing, pulsation cycle measurement processing, and swell cycle measurement processing will be described below. That is, as shown in FIG. 6 (a), the CPU 5a built in the μCOM 5 continuously supplies the heater resistor 14 with the electric current for the time tx for each predetermined time T1 longer than the predetermined time T2, and also performs the micro flow sensor 1 during the continuous driving. An analog amplified signal, which is an output of the amplifier 6 that amplifies a signal corresponding to the gas flow rate from the air, is sampled n3 times at intervals of sufficiently shorter than the minimum value 50 msec of the fluctuation cycle due to the pulsating flow, and each digital value is stored in the RAM 5c Store in. Then, based on the digital values stored in the RAM 5c, a pulsating flow detecting process and a pulsating cycle measuring process are respectively performed.

That is, in the pulsating flow detection process, n3
If the difference between the maximum value Qmax and the minimum value Qmin among the digital values of the amplified signal sampled twice is equal to or greater than a predetermined pulsation detection value, the presence of pulsation is detected, and If there is, no pulsation is detected. In the pulsating cycle measurement process, as shown in FIG. 6B, a time difference Tf1 between a point D1 at which the flow rate fluctuation increases from a decrease and a point D2 at which the flow rate increases and then decreases at the point D1 is obtained as a cycle. In addition, the point of rising from the above-mentioned falling and the point of falling from the above-mentioned are points D1,
In addition to the point D2, some are obtained, for example, points D3, D4,..., But the average value of the obtained time differences Tf1, Tf2,. It is also conceivable to set the minimum value of some obtained time differences Tf1, Tf2. Further, a time difference Tf3 between adjacent rising and falling points D2 and D4 may be obtained as a cycle.

The undulation detection processing and the undulation cycle measurement processing are respectively performed based on the moving average of the digital values stored in the RAM 5c. That is, by calculating the moving average value, even if the pulsation flows on the swell as shown in FIG. 6C, the short-time fluctuation due to the pulsation is canceled out, and the swell as shown in FIG. 6D. A digital value corresponding to only the flow rate fluctuation due to can be calculated. Therefore, in the undulation detection processing, of the moving average values of the digital values of the amplified signal sampled n3 times, the maximum moving average value Qave.max and the minimum moving average value Qav.
If the difference from e.min is equal to or greater than a predetermined swell detection value, the presence of swell is detected. If the difference is less than the swell detection value, no swell is detected.

Then, in the undulation cycle measuring process,
As shown in FIG. 6D, a point Dave.1 at which the moving average rises from a drop and a point D at which the moving average rises at the point Dave.1 and then falls.
The time difference Tf1 'from ave.2 is obtained as a cycle. Also,
The point of rising from the above descent and the point of falling from the above are point D
Some other than the ave.1 and the point Dave.2 are obtained, but the average value of the obtained time differences may be obtained as the cycle. It is also conceivable that the minimum value of some obtained time differences is used as the frequency.

As described above, in the pulsating flow detection processing and the swell detection processing, there is no need to provide any means for detecting the presence or absence of the pulsating flow or the swell from the digital value of the amplified signal sampled n3 times. Cost can be reduced. In addition, the pulsation cycle measurement processing and the swell cycle measurement processing are performed in order to measure the pulsation flow and the swell cycle in order to measure from the digital value sampled for the pulsation detection processing or the swell detection processing, respectively. Since it is not necessary to provide a separate unit, the cost can be reduced.

Further, in addition to the above-mentioned processing, the CPU 5a in the μCOM 5 functions as a passing flow rate integrating means, and integrates the passing flow rate obtained by the passing flow rate measuring processing to obtain an integrated flow rate. A display process or the like for displaying the integrated flow rate value obtained on the display unit 7 as a display unit is performed.

The detailed operation of the electronic gas meter incorporating the above-described flow rate measuring device will be described below with reference to the flowchart of FIG. 7 which describes the processing procedure of the CPU 5a of the μCOM 5. The CPU 5a starts the operation by turning on the battery power, for example, and performs initial settings of various areas formed in the RAM 5c in the μCOM 5 in an initial step (not shown), and then executes the first step S
Proceed to 1. In step S1, a control signal S1 is output to the micro flow sensor 1. This control signal S
Switch 2 is turned on in response to the output of
4 is energized by the drive pulse and is heated. Accordingly, a signal corresponding to the gas flow rate is output to the output terminal 19 of the micro flow sensor 1.

Thereafter, the CPU 5a proceeds to step S
2, an analog amplified signal obtained by amplifying a signal corresponding to the gas flow rate from the micro flow sensor 1 by the amplifier 6 is continuously sampled by the A / D converter 5 d at a high speed n3 times, and each digital sampled at a high speed is sampled. Value R
In the next step SP3, the output of the control signal S1 is stopped so that the heater resistor 1 of the micro flow sensor 1 is stored in the digital value area in the AM 5c.
4 is stopped.

Thereafter, the flow advances to step S4 to multiply the average value Qave.1 of the digital values sampled n3 times by the time tx required for n3 high-speed sampling times and the cross-sectional area S of the gas flow path 10 to obtain n3 times. The passing flow rate of the gas passed during the high-speed sampling is measured and stored in the passing flow rate area Qt in the RAM 5c. And the next step S
In step 5, the flow rate Qt obtained in step S4 is added to the flow rate accumulation area Q in the RAM 5c, and in step S6, the flow rate accumulation area Q is displayed on the display 7 in step S6.
Is displayed, and the process proceeds to the next step S7.

In step S7, a moving average value is calculated from the digital values stored in the digital value area in the RAM 5c and sampled n3 times at a high speed, and the moving average value is stored in the moving average value area in the RAM 5c. In the following step S8, the above-described undulation detection processing for detecting the presence or absence of undulation based on the moving average value area stored in the RAM 5c is executed. If the difference between the maximum value Qave.max and the minimum value Qave.min of the moving average exceeds the swell determination value, that is, if swell occurs at an amplitude exceeding the swell determination value, the determination in step S8 is YES. And the process proceeds to step S9. In step S9, the above-described undulation cycle measurement processing for measuring the undulation cycle based on the moving average value area is performed, and then, in step S10, for example, の of the undulation cycle measured in step S9 is set as a predetermined time T2. Second to reset
After performing the predetermined time setting process of step S1,
A passing flow rate measurement process is performed in the first third measurement mode.

The details of the flow rate measurement processing in the third measurement mode in step S11 are as follows. As shown in the flowchart of the CPU 5a in FIG. 8, the control signal S1 is output to the micro flow sensor 1 in the first step S11a. In response to the output of the control signal S1, a signal corresponding to the gas flow velocity is output to the output terminal 19 of the micro flow sensor 1. Thereafter, the CPU 5a proceeds to the subsequent step S1.
1b, an analog amplified signal obtained by amplifying a signal corresponding to the gas flow rate from the micro flow sensor 1 by the amplifier 6 is sampled once by the A / D converter 5d, and the sampled digital value is stored in the RAM 5c. In the next step S11c, the output of the control signal S1 is stopped to stop the energization of the heater resistor 14 of the micro flow sensor 1.

In the subsequent step S11d, the process waits for a lapse of a predetermined time T2 from the sampling in step S11b, and proceeds to the next step S11e.
It is determined whether or not the sampling of 1b has been continuously performed n2 times. If the sampling for every predetermined time T2 has not been performed continuously n2 times, the determination in step S11e is N
It becomes O, and sampling is repeated in step S11b again. As a result, when n2 samplings are continuously performed, the determination in step S11e becomes YES, and the process proceeds to the subsequent step S11f. By multiplying the average value Qave.3 of the digital values sampled n2 times in step S11f by the predetermined time T2 and the number of times n2, T1 *
The flow rate of the gas passing through every n2 intervals was measured, and RA
It is stored in the passing flow rate area Qt in M5c. In the next step S11g, the passing flow rate Qt obtained in step S11f is stored in the flow rate integrating area Q in the RAM 5c.
Is added, the content of the flow rate integration area Q is displayed on the display 7 in step S11h, and the next step S11
Proceeding to i, the flow returns after waiting for a predetermined time T1 from the start of the flow rate measurement process in the first measurement mode.

On the other hand, when the difference between the maximum value Qave.max and the minimum value Qave.min of the moving average value is smaller than the swell judgment value, that is, when the swell of the amplitude equal to or smaller than the swell judgment value is not generated. The determination in step S8 is NO, and in the subsequent step S12, the above-described pulsating flow detection processing for detecting the presence or absence of pulsating flow based on the digital value corresponding to the gas flow velocity stored in the digital value area in the RAM 5c is performed. Execute. That is, the maximum digital value Q
When the difference between max and the minimum value Qmin exceeds the pulsation flow determination value, that is, when pulsation occurs with an amplitude exceeding the pulsation flow determination value, the determination in step S12 becomes YES and step S1 is performed.
Proceed to 3. In the following step S13, the RAM 5
The above-described pulsation cycle measurement processing for measuring the pulsation cycle based on the digital value area of c is performed, and thereafter, step S1 is performed.
In step 4, an intermittent interval setting process for resetting, for example, １ ／ of the cycle of the pulsating flow measured in step S13 as the intermittent interval T4 is performed. Then, a flow rate measurement process in a second measurement mode in step S15 described later is performed.

The details of the flow rate measurement processing in the second measurement mode in step S15 are as follows. As shown in the flowchart of the CPU 5a in FIG. 9, the control signal S1 is output to the micro flow sensor 1 in the first step S15a. In response to the output of the control signal S1, a signal corresponding to the gas flow velocity is output to the output terminal 19 of the micro flow sensor 1. Thereafter, the CPU 5a proceeds to the subsequent step S1.
5b, an analog amplified signal obtained by amplifying a signal corresponding to the gas flow rate from the micro flow sensor 1 by the amplifier 6 is sampled once by the A / D converter 5d, and the sampled digital value is stored in the RAM 5c. Store in the value area.

Then, in the next step S15c,
Wait for the intermittent interval T4 to elapse after the sampling in step S15b is performed, and in subsequent step S15d, determine whether the sampling in step S15b has been performed n1 times in succession. If the sampling at every intermittent interval T4 has not been performed n1 times, the determination in step S15d is NO, and the sampling is repeated in step S15b. As a result, sampling is performed n1 times for each intermittent interval T4, and the determination in step S15d becomes YES, and the process proceeds to the next step S15e.

In step S15e, the control signal S
By stopping the output of the micro flow sensor 1
Of the heater resistor 14 is stopped. In the subsequent step S15f, the process waits for a lapse of a predetermined time T2 from the first sampling in the step S15b, and then proceeds to the next step S15g. In step S15b, the average value Qave.2 of the digital values sampled n1 times and the predetermined time T2
To measure the passing flow rate of the gas that has passed every predetermined time T2, and store it in the passing flow rate area Qt in the RAM 5c. In the next step S15h, the above-mentioned step S15 is stored in the flow rate integrating area Q in the RAM 5c.
After adding the passing flow rate Qt obtained at 15 g, step S
In step 15i, the contents of the flow rate accumulation area Q are displayed on the display 7, and the flow advances to the next step S15j, and the flow returns after waiting for a predetermined time T1 from the start of the flow rate measurement processing in the second measurement mode.

Further, the difference between the maximum value Qmax and the minimum value Qmin of the digital values stored in the digital value area does not exceed the pulsation determination value, that is, pulsation occurs with an amplitude equal to or less than the pulsation determination value. If there is no pulsating flow, step S
The determination in Step 12 becomes NO, and the process proceeds to Step S16 to perform the flow rate measurement processing in the first measurement mode.

The details of the flow rate measurement processing in the first measurement mode in step S16 are as follows. As shown in the flowchart of the CPU 5a in FIG. 10, the control signal S1 is output to the micro flow sensor 1 in the first step S16a. In response to the output of the control signal S1, a signal corresponding to the gas flow velocity is output to the output terminal 19 of the micro flow sensor 1. Thereafter, the CPU 5a proceeds to step S
Proceeding to 16b, an analog amplified signal obtained by amplifying a signal corresponding to the gas flow rate from the micro flow sensor 1 by the amplifier 6 is sampled once by the A / D converter 5d, and the sampled digital value is stored in the RAM 5c. In the next step S16c, the output of the control signal S1 is stopped to stop the energization of the heater resistor 14 of the micro flow sensor 1.

In the subsequent step S16d, the process waits for a lapse of a predetermined time T2 from the sampling in step S16b, and then proceeds to the next step S16e, where the process proceeds to step S1.
By multiplying the digital value sampled at 6b by a predetermined time T2, the passing flow rate of the gas passing every predetermined time T2 is measured, and the passing flow rate area Qt in the RAM 5c is measured.
To be stored. Then, in the next step S16f,
Step S16 is added to the flow rate accumulation area Q in the RAM 5c.
After adding the passing flow rate Qt obtained in step e, step S16
In step g, the display 7 displays the content of the flow rate accumulation area Q, and the process proceeds to the next step S16h, where a predetermined time T1 has elapsed since the flow rate measurement processing in the first measurement mode was started.
Waits for elapse and returns.

As shown in the above-described flowchart, in the above embodiment, when the presence of swell is detected by the swell detection processing in step S8, the third measurement mode is set regardless of the presence or absence of pulsation. However, for example, if there is swell and pulsation, the second
Average value Q of digital values sampled n1 times at intermittent intervals T4 every predetermined time T2 obtained in the measurement mode
average value of ave.2 calculated n2 times, predetermined time T2 and number of times n
The passing flow rate may be obtained by multiplying twice and the cross-sectional area of the gas flow path. In this way, it is possible to cancel the fluctuation due to the pulsating flow by obtaining the average value Qave.2, and further cancel the fluctuation due to the swell by taking the average of the average value Qave.2 obtained n2 times every predetermined time T2. it can.

In the above-described embodiment, the detection of the presence of a pulsating flow is performed based on the judgment value of Qmax-Qmin> pulsating flow. However, in a gas meter having no function such as a total flow cutoff, the pulsating flow is canceled when there is a flow. Because there is not much need to do
If the presence of pulsation is detected based on (Qmax-Qmin) / Qmin> pulsation flow determination value, the pulsation having a small vibration width can be ignored when the flow rate is large.

In the above-described embodiment, the cycle of the pulsating flow is measured each time a pulsating flow is detected, and the swelling cycle is measured each time the swelling is detected, and the intermittent interval T4 or the predetermined time T2 is set. However, for example, resetting of the intermittent interval T4 and the first predetermined time T4 by the intermittent interval setting processing and the second predetermined time setting processing is performed every one month (third predetermined time) longer than the predetermined time T1. It may be performed. Specifically, the pulsation or swell measurement was performed during the learning period when the pulsation or swell was detected after the third day, with the first three days of one month being the learning period. The passing flow rate may be measured in the second or third measurement mode at the intermittent interval T4 or the predetermined time T2 based on the pulsating cycle and the swell cycle. If a plurality of pulsating or swelling periods can be measured during the learning period, the period may be obtained from the average value, or the intermittent interval T4 and the predetermined time T2 may be set based on the smallest one among the plurality. You may fix it.

As described above, by performing the second measurement mode in accordance with the intermittent interval T4 or the predetermined time T2 set based on the pulsating or swelling cycle measured during the learning period, the pulsating flow may occur during periods other than the learning period. Alternatively, it is not necessary to determine the cycle every time the presence of the swell is detected, so that the power consumption required to determine the cycle can be reduced. Also,
Even if the usage mode of the burning appliance changes depending on the season, the intermittent interval T is set based on the pulsation or swell cycle that changes according to the usage mode by providing a learning period every month.
Since 4 or the predetermined time T2 can be reset, it is possible to obtain a flow measurement device capable of reducing power consumption without further lowering the flow measurement accuracy.

In the above-described embodiment, the presence or absence of a pulsating flow is always detected at every predetermined time T1.
A detection stop switch SW1 (= detection stop means), which is connected to the OM 5 and disables the pulsating flow detection process when turned on, is provided in the operation unit of the electronic gas meter, and GHP or the like which causes the pulsating flow is set in advance. Only when it is known that the pulsating flow is detected, the detection stop switch SW1 may be turned off so that the pulsating flow detection process can be executed every predetermined time T1. By doing so, it is possible to reduce the power consumption for the pulsating flow detection process when there is no cause of the pulsating flow.

Further, the detection stop switch SW1
Is provided in the operation unit of the electronic gas meter. For example, the detection stop switch SW1 can be turned on in response to a detection stop signal transmitted via a communication line by remote control from a gas company or a management company. Is also good. In this case, an employee of the gas company or the management company does not have to go to the place where the flow rate measuring device is installed, and the cost can be reduced.

[0084]

As described above, according to the first aspect of the present invention, there is no need to calculate the passing flow rate by consuming a large amount of power despite the absence of a pulsating flow. Since the instantaneous flow rate can be measured, wasteful power is not consumed, so that a flow rate measurement method capable of reducing power consumption without lowering the flow rate measurement accuracy can be obtained.

According to the second aspect of the present invention, even though there is no pulsating flow, it is not necessary to consume a large amount of power in the second measurement mode to obtain the passing flow rate, and to reduce the power in the first measurement mode. Since the instantaneous flow rate can be accurately measured while suppressing the flow rate, wasteful power is not consumed. Therefore, it is possible to obtain a flow rate measurement apparatus capable of reducing power consumption without lowering the flow rate measurement accuracy. .

According to the third aspect of the present invention, the peak portion and the valley portion of the flow fluctuation caused by the pulsating flow can be measured in the intermittent plural times of measurement, so that the fluctuation of the flow is offset by averaging. Therefore, it is possible to obtain a flow rate measuring device with improved flow rate measurement accuracy.

According to the fourth aspect of the present invention, if a physical quantity is measured, there is no need to provide any separate means for detecting the presence or absence of a pulsating flow. Obtainable.

According to the fifth aspect of the present invention, the physical quantity can be measured at every intermittent interval corresponding to the cycle of the pulsating flow. Since the measurement is not performed in a short intermittent time corresponding to the time and wasteful power is not consumed, the power consumption can be reduced without further lowering the flow rate measurement accuracy. In addition, since it is not necessary to provide any additional means for detecting the period of the pulsating flow, it is possible to obtain a flow measuring device with reduced cost.

According to the sixth aspect of the present invention, the second intermittent flow rate measurement interval set by the intermittent interval setting means based on the pulsating cycle measured by the pulsating cycle measuring means during the learning period. By performing the measurement mode, it is not necessary to calculate the cycle every time the presence of the pulsating flow is detected during the period other than the learning period, and the power consumption for obtaining the cycle can be reduced. Further, even if the usage mode of the burning appliance changes depending on the season, the learning period is provided at every third predetermined time, so that the intermittent physical quantity measurement can be performed based on the cycle of the pulsating flow that changes according to the usage mode. Since the interval can be set again, it is possible to obtain a flow rate measurement device capable of reducing power consumption without further lowering the flow rate measurement accuracy.

According to the seventh aspect of the present invention, as the gas flows through the bent pipe, the flow velocity of the gas is adjusted. As a result, swelling, which is a flow fluctuation with a period larger than the pulsating flow by the gas heat pump, may occur. Therefore, when the swell detection means detects the presence of swell, if the average value of the physical quantities measured a plurality of times at the first predetermined time is taken, the fluctuation due to the swell can be canceled out, so that the flow rate measurement accuracy is further improved. Thus, a flow measurement device that has been operated can be obtained.

According to the eighth aspect of the present invention, the peak and the valley of the flow fluctuation due to undulation can be measured in a plurality of measurements every second predetermined time, so that the fluctuation of the flow is averaged. Since the flow rate can be canceled out, it is possible to obtain a flow rate measuring device with improved flow rate measurement accuracy.

According to the ninth aspect of the present invention, the presence or absence of undulation can be detected by measuring the physical quantity, so that there is no need to provide any separate means for detecting the presence or absence of undulation, thereby reducing cost. Thus, a flow rate measuring device can be obtained.

According to the tenth aspect, since the physical quantity can be measured at every second predetermined time according to the cycle of the swell, the swell of a short cycle despite the occurrence of the swell of a relatively long cycle. Since the measurement is not performed in the second predetermined time corresponding to the time and the wasteful power is not consumed, the power consumption can be reduced without further lowering the flow rate measurement accuracy. Moreover, since the swell period measuring means measures the swell cycle based on the physical quantity measured a plurality of times by the swell detection means, there is no need to provide any additional means for detecting the swell cycle, thereby reducing costs. The intended flow rate measuring device can be obtained.

According to the eleventh aspect of the present invention, the third measurement is performed in accordance with the second predetermined time set by the second predetermined time setting means based on the swell cycle measured by the swell cycle measurement means during the learning period. By performing the mode, it is not necessary to calculate the cycle every time the presence of the swell is detected during the period other than the learning period, and the power consumption required for calculating the cycle can be reduced. In addition, even if the usage mode of the burning appliance changes depending on the season, the learning period is provided every third predetermined time period, so that the second predetermined time period is set based on the swell cycle that changes according to the usage mode. Therefore, it is possible to obtain a flow measurement device capable of reducing power consumption without further lowering the flow measurement accuracy.

According to the twelfth aspect of the present invention, when it is known in advance that a gas heat pump or the like serving as a pulsating flow source is installed in one's own or a neighboring house, detection of pulsating flow is stopped by the detection stopping means. If so, the power consumption associated with the pulsating flow detection can be reduced, so that a flow measurement device that can reduce the power consumption can be obtained.

According to the thirteenth aspect of the present invention, the detection of the pulsating flow by the pulsating flow detecting means is stopped by a remote operation from within a gas company or a management company which grasps the use state of the gas heat pump, that is, from outside. Therefore, the labor of the gas company or the management company does not have to go to the place where the flow rate measuring device is installed, and a flow rate measuring device with reduced cost can be obtained.

According to the fourteenth aspect of the present invention, it is possible to accumulate and display the accurate passing flow rate measured by the flow rate measuring device capable of further reducing the power consumption without lowering the flow rate measuring accuracy. Therefore, it is possible to obtain an electronic gas meter capable of reducing the error in the flow rate and accurately integrating and displaying the gas usage.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration diagram of an electronic gas meter incorporating a flow rate measuring device according to the present invention.

FIG. 2 is a diagram showing an embodiment of an electronic gas meter incorporating the flow rate measuring device according to the present invention.

FIG. 3 is a diagram showing details of the micro flow sensor of FIG. 2;

FIG. 4 is a circuit diagram showing details of the micro flow sensor of FIG. 2;

FIG. 5 is a diagram for explaining passing flow rate measurement in first, second, and third measurement modes.

FIG. 6 is a diagram for explaining details of a pulsation detection process, a swell detection process, a pulsation cycle measurement process, and a swell cycle measurement process by the CPU of FIG. 1;

FIG. 7 is a CPU constituting the microcomputer of FIG. 2;
6 is a flowchart showing a processing procedure of FIG.

FIG. 8 is a flowchart for explaining details of a flow rate measurement in a third measurement mode shown in FIG. 7;

FIG. 9 is a flowchart for explaining details of the flow rate measurement in the second measurement mode shown in FIG. 7;

FIG. 10 is a flowchart for explaining details of the flow rate measurement in the third measurement mode shown in FIG. 7;

FIG. 11 is a view for explaining a problem of a conventional flow rate measuring device and an electronic gas meter.

[Description of Signs] T1 First predetermined time 5a-1 Passing flow rate measuring means (CPU) T2 Second predetermined time 5a-2 Pulse flow detecting means (CPU) 5a-3 Measurement mode selecting means (CPU) 5a-4 Pulsation cycle measuring means (CPU) 5a-5 Intermittent interval setting means (CPU) 5a-6 Swell detecting means (CPU) 5a-7 Swell cycle measuring means (CPU) 5a-8 Second predetermined time setting means (CPU) SW1 Detection stop means (detection stop switch) 5a-9 Flow rate integration means (CPU) 7 Display means (display)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ikko Ikko 1-5-20 Kaigan, Minato-ku, Tokyo Inside Tokyo Gas Co., Ltd. (72) Inventor Minoru Seto 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Inventor Kenchi Kobayashi 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. GA02

Claims (14)

[Claims] 1. A method according to claim 1, wherein the presence or absence of a pulsating flow, which is a flow rate fluctuation, is detected at every first predetermined time. 2nd shorter than the predetermined time
The physical quantity is measured intermittently a plurality of times at the second predetermined time, and the flow rate is measured based on the measured physical quantity. A flow rate measuring method characterized by measuring a passing flow rate based on an average value of measured physical quantities. 2. A pulsating flow detecting means for detecting the presence or absence of a pulsating flow, which is a flow fluctuation at every first predetermined time, and a physical quantity changing according to a gas flow rate in the gas flow path is set to the first predetermined time. Measuring at a shorter second predetermined time,
A first measurement mode for measuring the passing flow rate based on the measured physical quantity, and the intermittent measurement of the physical quantity a plurality of times every the second predetermined time, and a passing flow rate based on an average value of the physical quantities measured a plurality of times. Of the second measurement mode for measuring
A flow rate measuring means operable in one of the selected measurement modes, a first measurement mode when no pulsation is detected by the pulsation detection means, and a second measurement mode when pulsation is detected by the pulsation detection means. And a measurement mode selecting means for causing the passing flow rate measuring means to measure the passing flow rate in the selected measurement mode. 3. The flow measurement device according to claim 2, wherein an interval of the intermittent physical quantity measurement in the second measurement mode is set to be less than a cycle of the pulsating flow. 4. The pulsating flow detecting means detects the presence or absence of a pulsating flow based on physical quantities measured a plurality of times at intervals shorter than a minimum value of the period of the pulsating flow.
The flow measurement device as described. 5. When the pulsating flow detecting means detects the presence of a pulsating flow, a pulsating cycle measuring means for measuring a pulsating cycle based on physical quantities measured a plurality of times by the pulsating flow detecting means; 5. The apparatus according to claim 2, further comprising an intermittent interval setting unit that resets an interval of the intermittent physical quantity measurement in the second measurement mode based on a cycle measured by the flow cycle measuring unit. 6. Flow measuring device. 6. The pulsating flow measuring means detects a pulsating flow detected by the pulsating flow detecting means only during a learning period provided at every third predetermined time longer than the first predetermined time. The intermittent interval setting means resets the intermittent physical quantity measurement interval based on the cycle measured by the pulsating cycle measuring means during the learning period. 5. The flow measuring device according to 5. 7. A swell detecting means for detecting presence or absence of swell which is a flow fluctuation of a cycle longer than the pulsating flow at each timing synchronized with the pulsating flow detecting means, wherein the passing flow rate measuring means comprises A third measurement mode for measuring the passing flow rate based on the average value of the physical quantities measured a plurality of times every predetermined time can be further selected, and the measurement mode selection means detects the presence of the swell by the swell detection means 7. The flow measurement device according to claim 2, wherein the third measurement mode is selected at the time. 8. The second measurement mode in the third measurement mode.
The flow rate measuring device according to claim 7, wherein the predetermined time is set to be less than the cycle of the undulation. 9. The undulation detecting means detects the presence or absence of undulation based on a moving average of physical quantities measured a plurality of times at intervals shorter than the minimum value of the cycle of the pulsating flow. 8. The flow measurement device according to 8. 10. A swell cycle measuring means for measuring a swell cycle based on a moving average of physical quantities measured a plurality of times by the swell detection means when the swell detection means detects the presence of a swell. The flow rate measuring device according to any one of claims 7 to 9, further comprising second predetermined time setting means for resetting the second predetermined time based on a cycle measured by the means. 11. The swell cycle measuring means measures a swell cycle when the swell detection means detects the presence of swell only in a learning period provided at every third predetermined time longer than the first predetermined time. The flow rate measuring apparatus according to claim 10, wherein the second predetermined time setting means resets the second predetermined time based on a cycle measured by the swell cycle measuring means during a learning period. . 12. The flow rate measuring device according to claim 2, further comprising a detection stopping means for stopping detection of the presence or absence of a pulsating flow by said pulsating flow detecting means. 13. The detecting means according to claim 12, wherein said detecting means stops detecting the presence or absence of a pulsating flow by said pulsating flow detecting means in response to a detecting stop signal transmitted from outside via a communication line. The flow measurement device as described. 14. A flow rate measuring device according to claim 2, wherein a flow rate integrating means for integrating a passing flow rate of gas measured in a measurement mode selected by said measurement mode selecting means, and a flow rate integrating means. A display means for displaying the flow rate integrated by the electronic gas meter.