JP2001296165A - Flow rate measuring device and electronic flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate measuring device for further reducing the power consumption, without bringing about a decrease in flow rate measuring accuracy. SOLUTION: A flowing speed sensor 1 outputs an analog flowing speed signal, in response to a flowing speed of a fluid in a channel. A drive means 5a-1 intermittently drives the sensor 1 for a prescribed time. An integrating means 7 outputs an integrated value of the analog signal, that is, an analog integrated value signal, in response to the passing flow rate of the fluid passing during driving of the sensor 1. A digital conversion means 8 samples the integrated value signal, in response to the passing flow rate of the fluid passing for a prescribed time upon the lapse of every predetermined time which is longer than the period of a pulsating current from the start of driving for a predetermined time by the means 5a-1, converts the signal into a digital value, and measures the passing flow rate of the fluid passing within an intermittent time, based on the digital value of the analog integrated value signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device for measuring the flow rate of a fluid such as gas, and an electronic flow meter for integrating and displaying the flow rate of the fluid measured by the device. A flow rate measuring device including a flow rate sensor that outputs an analog flow rate signal corresponding to the flow rate of the fluid,
The present invention relates to an electronic flow meter.

[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 measuring device comprises a flow rate sensor composed of 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. Utilizing the fact that changes with the magnitude of the flow velocity, the A / D converter intermittently samples the analog flow velocity signal corresponding to the temperature difference detected by the temperature sensor provided upstream and downstream of the heater by the A / D converter, thereby controlling the flow velocity. It is measured indirectly. Note that the flow velocity sensor is intermittently driven according to sampling timing in order to suppress power consumption.

[0003]

Some of the combustors that consume gas supplied through an electronic gas meter (= electronic flow meter) cause pressure fluctuations in the supplied gas pressure during use. For example, in the case of a GHP (gas heat pump), the use of the
the variation of mmH ₂ O to produce at a frequency of 5~20Hz. 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 consumer house in an apartment house or the like, the pressure fluctuation caused by the GHP occurs. Since an instantaneous gas flow occurs in the gas flow path in the gas meter, a time difference corresponding to a certain flow rate is measured. If this is mistaken for the gas flow rate due to gas consumption and the flow rate integrated value is calculated by integrating it as the passing flow rate, the integrated value becomes larger than the actual gas consumption, which is fatal for a measuring instrument. Reliability issues.

[0004] That is, when pressure fluctuations occur in the electronic gas meter as shown in FIG. 9 (a) 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 fluctuations. 9B, a pulsating flow of 10 to 20 Hz occurs as shown in FIG. 9B. If intermittent measurements were taken in response to this,
The passing flow rate as shown in FIG. 9C is obtained, and the passing flow rate Ta measured at the timing a is integrated.

If the pressure generated by the above-mentioned GHP fluctuates upstream of the electronic gas meter in the consumer house consuming gas, the flow rate in the gas flow path of the electronic gas meter in the consumer house changes as shown in FIG. The increase / decrease is repeated as shown in FIG. Then, when a flow rate that repeatedly increases and decreases such an actual flow rate is determined by an electronic gas meter, as in recent years,
When a security function such as a gas leak detection function and a gas leak alarm function and a gas supply cutoff function associated therewith are mounted on an electronic 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, as an electronic gas meter incorporating a flow rate measuring device for solving the above-mentioned problem, Japanese Patent Application Laid-Open No.
There is a gas flow meter disclosed in 15006 publication. This gas flow meter calculates the average value of the physical quantity of the digital value of the analog flow velocity signal according to the flow velocity obtained by sampling n1 times at the intermittent time T4 every predetermined time T1 as shown in FIG. The gas flow rate is measured based on this. 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. However, the gas flow meter disclosed in Japanese Patent Application Laid-Open No. 9-15006 improves the flow rate measurement accuracy, but performs n1 continuous samplings every predetermined time T1 to obtain an average value. There is a problem that the power consumption is large.

[0008] Therefore, the present invention focuses on the above-mentioned problems, and an object of the present invention is to provide a flow rate measuring device capable of further reducing power consumption without lowering the flow rate measuring accuracy.

Another object of the present invention is to provide an electronic flow meter capable of reducing the error in the flow rate and accurately displaying the accumulated amount of fluid even if the power consumption is reduced.

[0010]

According to a first aspect of the present invention, there is provided a flow rate sensor for outputting an analog flow rate signal corresponding to a flow rate of a fluid in a flow path.
Driving means 5a for intermittently driving the flow rate sensor for a predetermined time
-1, an integrating means 7 for integrating an analog flow rate signal output by the flow rate sensor and outputting an analog integrated value signal corresponding to the integrated value, and a pulsating flow after the driving for a predetermined time is started by the driving means. Digital conversion means 8 for sampling the analog integrated value signal each time a predetermined time longer than the period of the digital integrated circuit elapses, and digitally converting the sampled analog integrated signal, the analog integrated value signal converted by the digital converting means. The flow rate of a fluid passing through the flow path within the intermittent time is measured based on the digital value of the flow rate.

According to the first aspect of the invention, the flow velocity sensor 1 outputs an analog flow velocity signal corresponding to the flow velocity of the fluid in the flow path, and the driving means 5a-1 intermittently drives the flow velocity sensor 1 for a predetermined time. And the integrating means 7 calculates the integrated value of the analog flow velocity signal,
That is, an analog integrated value signal is output according to the flow rate of the fluid passing while the flow velocity sensor 1 is being driven, and the digital conversion means 8 is driven by the driving means 5a-1 for a predetermined period of time to determine the period of the pulsating flow. Each time a long period of time elapses, the analog integrated signal corresponding to the flow rate of the fluid that has passed within the fixed time is sampled and converted into a digital value, and the signal is passed within the intermittent time based on the digital value of the analog integrated signal. The flow rate of the flowing fluid is measured. Therefore, even if the flow rate fluctuation is caused by the pulsating flow, the analog flow velocity signal corresponding to the flow velocity of the fluid is integrated, that is, continuously integrated, thereby canceling out the fluctuation and eliminating the influence of the pulsating flow. Moreover, an analog integrated value signal corresponding to the integrated value of the analog flow velocity signal is passed within an intermittent time based on a digital value sampled every time a predetermined time longer than the period of the pulsating flow has elapsed since the drive of the flow velocity sensor 1 was started. By measuring the flow rate of the fluid, the accurate flow rate of the fluid, which eliminates the influence of the pulsating flow passing within the intermittent time, can be reduced to 1
It can be obtained by sampling twice.

[0012] According to a second aspect of the present invention, the predetermined time is:
The flow rate measuring device according to claim 1, wherein the time is equal to the predetermined time.

According to the second aspect of the present invention, since the predetermined time is equal to the predetermined time, the counting means for counting the predetermined time can be used for counting the predetermined time.

According to a third aspect of the present invention, the driving means includes:
3. The flow measuring device according to claim 2, further comprising a predetermined time setting means for resetting the predetermined time.

According to the third aspect of the present invention, the driving means 5
a-1 has the predetermined time setting means 10 for resetting the predetermined time. For example, when the rotation cycle of the gas heat pump which is one of the causes of the pulsating flow is known in advance, the predetermined time setting means 10 If the time is set to the period of the pulsating flow determined by the rotation period, the fluctuation of the pulsating flow can be completely canceled by integrating one period.
Moreover, when a pulsating flow having a period shorter than the maximum period of the pulsating flow is generated, a predetermined time is set according to the short period without setting the predetermined period for the maximum period of the pulsating flow, so that wasteful power is consumed. Consumption can be reduced.

According to a fourth aspect of the present invention, the predetermined time setting means resets the predetermined time in response to a predetermined time signal transmitted via an external communication line. In the described flow rate measuring device.

According to the fourth aspect of the present invention, the predetermined time setting means resets the predetermined time in accordance with the predetermined time signal transmitted via an external communication line. The predetermined time can be set within a gas company or management company that is aware of one of the causes, ie, the usage status of the gas heat pump, by remote control from outside.

According to a fifth aspect of the present invention, there is provided the flow rate measuring device according to any one of the first to fourth aspects, wherein the fluid is a fuel gas supplied to a gas combustor.

According to the fifth aspect of the present invention, even if the flow rate fluctuation occurs due to the pulsating flow, the fluctuation amount is canceled by integrating the analog flow rate signal corresponding to the passing flow rate of the fuel gas, that is, continuously integrating the analog flow rate signal. , Eliminates the effects of pulsating flow. In addition, an accurate flow rate of the fuel gas from which the influence of the pulsating flow passing in the intermittent time is removed can be obtained by one sampling.

According to a sixth aspect of the present invention, there is provided a flow rate measuring apparatus according to any one of the first to fifth aspects, and a flow rate integrating means for integrating a flow rate of the fluid passing through the intermittent time measured by the flow rate measuring apparatus. -2, and a display means 9 for displaying the integrated flow rate integrated by the flow rate integrating means.

According to a sixth aspect of the present invention, the flow rate integrating means 5a-2 integrates the passing flow rate of the fluid passing within the intermittent time measured by the flow rate measuring apparatus according to the first to fourth aspects, and displays the display means. Displays the integrated flow rate integrated by the flow rate integrating means 5a-2. Thus, a flow measurement device capable of further reducing power consumption by reducing wasteful power consumption without lowering flow measurement accuracy. Accurate measured flow rates can be integrated and displayed.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an electronic flow meter incorporating the flow measuring device of the present invention. This electronic flow meter is referred to as an electronic gas meter for measuring fuel gas as a fluid in the embodiment of the present invention. The illustrated electronic gas meter is of a thermal type, and has a micro flow sensor 1 as a flow sensor that outputs an analog flow signal according to the flow speed of gas.

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), and sensor resistors 12 and 13 for temperature measurement and a heater resistor 14 for heating formed on the thin film layer. The sensor resistor 12, the heater resistor 14, and the sensor resistor 13 are arranged at regular intervals along the flow direction D in this order from the upstream side in the flow direction D.

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 a voltage from the battery 31 as a predetermined constant voltage by the constant voltage circuit 33. Switch 2 is a microcomputer (hereinafter referred to as a microcomputer).
It turns on in response to the output of the H-level 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
Power supply 3 according to H-level control signal S1 from COM5.
And is heated by a predetermined constant voltage output from the heater.

The sensor resistors 12 and 13 are connected in series, as shown in an equivalent circuit diagram in FIG. 4, and a bridge circuit 17 is connected together with reference resistors 15 and 16 which are connected in series separately. Make up. The bridge circuit 17 receives the constant current from the constant current circuit 18 connected to the connection point between the sensor resistor 12 and the reference resistor 15 to change the sensor resistor 12 depending on the ambient temperature.
A signal corresponding to the difference between the resistance values of the reference resistors 15 and 16 is connected at one end to the connection point a of the sensor resistors 12 and 13 and at the other end.
Differential amplifiers 19 connected to the connection point b of the
It is configured to output from.

Here, the principle of the micro flow sensor 1 having the above configuration will be described below. Heater resistor 14
Is supplied with a predetermined constant voltage from the power supply 3 at the same time as the output of the control signal S1 from the μCOM 5 to perform heating.
As a result, when gas is not flowing through the gas passage 10,
Heat is transmitted to the gas near the heater resistor 14, and the upstream and downstream temperature distribution near the heater resistor 14 becomes the target distribution. That is, since the temperatures of the sensor resistors 12 and 13 rise to the same temperature, the resistance values of the sensor resistors 12 and 13 are substantially equal, and the output from the output terminal 19 is substantially zero.

On the other hand, when the gas flows in the gas flow direction D in FIG. 3 while the heater resistor 14 is energized, the upstream side is cooled and the temperature drops. On the downstream side, the heat conduction is promoted from the heater resistor 14 by using the gas flow as a medium to increase the temperature. As a result, the sensor resistor 12 upstream of the heater resistor 14
The resistance value of the sensor resistor 13 on the downstream side decreases because the temperature is decreased by gas, and the resistance value decreases because the temperature of the sensor resistor 13 on the downstream side is decreased by gas. When the flow rate increases, the above-mentioned temperature drop and temperature rise also increase, so the sensor resistance 1
The output from the output terminal 19, which is the difference between the resistance values 2 and 13, is an output corresponding to the flow velocity. After the analog flow rate signal from the differential amplifier 19 of the micro flow sensor 1 corresponding to the flow rate of the gas is amplified by the amplifier 6, the resistance R
1 and R2, and a capacitor C, and are output to an integration circuit 7 as integration means for integrating the analog flow rate signal amplified by the amplifier 6.

From the above-mentioned μCOM5, the control signal S1 in which the H-level period is 200 msec for a predetermined time is intermittent time 1s
5A, the heater resistor 14 is continuously energized for 200 msec every 1 s as shown in FIG. 5A. As a result, the micro flow sensor 1 is intermittently driven continuously for a predetermined time of 200 msec, and the analog flow rate signal is output intermittently as shown in FIG. Therefore, the integrating circuit 7 operates for a predetermined time 20 as shown in FIG.
The integrated value of the analog flow velocity signal output by the micro flow sensor 1 during the continuous driving of 0 msec, that is, the predetermined time 200
An analog integrated value signal corresponding to the flow rate of gas passing during continuous driving for msec is output to the A / D converter 8 as digital conversion means.

The above-mentioned A / D converter 8 samples the analog integrated signal from the integrating circuit 7 at each timing a when the continuous driving of the micro flow sensor 1 is stopped, and digitally converts the sampled analog integrated signal. The value is output to μCOM5. That is, A / D
The converter 8 samples an analog integrated value signal corresponding to the flow rate of the gas that has passed during the predetermined time of 200 msec during which the micro flow sensor 1 is continuously driven, and outputs the digital value 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 the like, which are interconnected by a bus line (not shown).

The CPU 5a in the μCOM 5 intermittently outputs the control signal S1 to drive the micro flow sensor 1 to intermittently output the analog flow rate signal corresponding to the gas flow rate, and the A / D converter. 8, the micro flow sensor 1 obtained by the conversion is continuously driven 200.
The digital value of the analog integrated value signal corresponding to the flow rate of the gas that has passed during msec and the intermittent time 1 s / predetermined time 200
Multiplied by msec to calculate the passing flow rate of the gas passing within the intermittent time 1 s, the flow rate calculation processing, and the flow rate integration processing obtained by integrating the flow rates calculated by the passing flow rate calculation processing (= function as flow rate integration means) ), Display processing for displaying the integrated flow rate value obtained by the flow integration processing on the display 9 as display means is performed. As is clear from the above, the CPU 5a functions as a driving unit and a flow rate integrating unit.

The operation of the electronic gas meter incorporating the above-structured flow rate measuring device will be described below with reference to the time chart of FIG. The CPU 5a in the μCOM 5 outputs the control signal S1 having the H-level period of 200 msec every 1 s of the intermittent time, and intermittently drives the micro flow sensor 1 for a predetermined time of 200 msec (FIG. 6A). Therefore, the micro flow sensor 1 intermittently outputs an analog flow rate signal corresponding to the gas flow rate (FIG. 6B). now,
If GHP is used with gas used, GHP
The gas flow rate fluctuates due to the pressure fluctuation, and the analog flow velocity signal has a waveform in which a pulsating flow is generated as shown in FIG. As a result of charging the capacitor C via the resistor R1 in the integration circuit 7, the integration circuit 7 outputs an analog integration signal as shown in FIG.

Therefore, the analog integrated value signal α at the timing a at which the continuous driving of the micro flow sensor 1 is stopped
Is a value corresponding to the flow rate of the gas passing during the continuous driving of the micro flow sensor 1 for 200 msec. Therefore, if sampling is performed by the A / D converter 8 at the timing a, a digital value of the analog integrated value signal α corresponding to the flow rate of the gas passing during the above-described continuous driving is obtained.
Then, the CPU 5a calculates the passing flow rate of the gas passing within the intermittent time 1 s by multiplying the digital value and the value obtained by dividing the intermittent time 1 s by the predetermined time 200 msec and the sectional area of the gas flow path 10.

On the other hand, if GHP is used in a state where no gas is used, the analog flow rate signal becomes as shown in FIG.
It becomes as shown in. For this reason, in the integration circuit 7, when the analog flow velocity signal has a positive value, the capacitor C is charged via the resistor R1, and when the analog flow rate signal has a negative value, the charge charged on the capacitor C passes through the resistor R2. As a result, an analog integrated value signal as shown in FIG. 7B obtained by integrating the analog flow velocity signal is output. The CPU 5a determines that there is no flow rate if the maximum value β of the analog integrated value signal according to the integrated value of the analog flow velocity signal when the pulsating flow is generated at the flow rate 0 is zero. Even if the flow rate is relatively large, it is not recognized that there is a flow rate.

As described above, the cycle of the pulsating flow is 50
Since it is about msec to 200 msec, if the predetermined time is set to the maximum cycle of the pulsating flow of 200 msec, the pulsating flow of at least one cycle or more is integrated. In this way, even if the flow rate fluctuation occurs due to the pulsating flow, the analog flow velocity signal corresponding to the gas flow velocity is integrated, that is, the fluctuation amount is canceled by continuously integrating, and the influence of the pulsating flow is removed. Can be. In addition, by measuring the flow rate of the gas passing through the intermittent time 1 s based on the digital value sampled each time the continuous driving of the micro flow sensor 1 stops, the analog integrated value signal corresponding to the integrated value of the analog flow velocity signal is measured. It is possible to obtain an accurate flow rate of gas by eliminating the influence of the pulsating flow passing within the intermittent time 1s by one sampling, thereby further reducing power consumption without lowering flow rate measurement accuracy. Can be achieved.

The details of the operation of the electronic gas meter incorporating the flow rate measuring device described above will be described below with reference to FIG. 8 showing the processing procedure of the CPU 5a. 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 proceeds to the first step S1. Here, the control signal S1 is output to drive the micro flow sensor 1. After a predetermined time of 200 msec has elapsed since the micro flow sensor 1 was driven in the next step S2, that is, after the continuous driving of 200 msec is performed, the process proceeds to step S3, where the analog integrated value signal from the integration circuit 7 is converted to A / A. By sampling by the D converter 8, a digital value Qd corresponding to the flow rate of the gas passing through the gas flow path 10 during the continuous driving for 200 msec is captured. Thereafter, the process proceeds to step S4, in which the output of the control signal S1 is stopped to stop driving the micro flow sensor 1, and the process proceeds to step S5.

In step S5, it is determined whether or not the digital value Qd of the analog integrated value signal according to the flow rate of the gas that has passed in 200 msec sampled in step S3 exceeds β, that is, a flow rate that can be regarded as having a flow rate. Is determined. If the digital value Qd exceeds β and it can be considered that there is a flow rate, the intermittent time 1 s is obtained by multiplying the cross-sectional area of the gas flow path 10 by the value obtained by dividing the digital value Qd and the predetermined time 1 s by the intermittent time 200 msec in subsequent step S 6. Is determined and stored in the flow rate area Qt formed in the RAM 5c. Thereafter, the process proceeds to step S7, where the passing flow rate area Qt is added to the flow rate integration count area Q and stored, and thereafter, step S8 is performed.
After performing the display processing for displaying the contents of the flow rate integrated count area Q on the display 8 in step, the process proceeds to step S9 described later.

On the other hand, in step S5, the digital value Qd becomes β
In the following, that is, when the gas is not used and the flow rate can be regarded as 0, the process immediately proceeds to step S9. In the following step S9, the micro flow sensor 1 waits until the intermittent time 1s elapses after outputting the control signal S1 in step S1 and returns to step S1, so that the micro flow sensor 1
It is continuously driven for a predetermined time of 200 msec every s.

In the above-described embodiment, the analog integrated value signal is sampled by the A / D converter 8 every time the continuous driving of the micro flow sensor 1 for a predetermined time of 200 msec is stopped. Time 200ms
Before the continuous drive of ec is stopped,
Even if the analog integrated signal is sampled by the A / D converter 8 every time a predetermined time longer than the period of the pulsating flow elapses from the start of continuous driving of 0 msec, the same effect as in the above embodiment can be obtained. However, as in the above-described embodiment, each time continuous driving for a predetermined time of 200 msec is stopped, that is, if the predetermined time of 200 msec is equal to the fixed time, a means for counting the predetermined time of 200 msec and the fixed time is separately provided. Since there is no need, cost can be reduced.

In the above-described embodiment, the predetermined time (=
The predetermined time is fixedly set to 200 msec. However, for example, the variable resistor 10 (= predetermined time setting means) is connected to the μCOM 5 and the CPU 5a
A predetermined time according to a resistance value of 0 may be set. With such a configuration, when the rotation cycle of the GHP, which is the cause of the pulsation, is known in advance, the resistance value of the variable resistor 10 is adjusted to set the predetermined time to the cycle of the pulsation determined by the rotation cycle of the GHP. In this case, if the integration circuit 7 integrates one cycle of the pulsating flow of the analog flow velocity signal, the fluctuation of the pulsating flow can be completely canceled. In addition, when a pulsating flow shorter than the maximum pulsating period of 200 msec is generated, a predetermined time corresponding to the short period is set without driving at the maximum period of the pulsating flow, thereby reducing wasteful power consumption. Can be.

The above-mentioned predetermined time may be set to a value corresponding to a predetermined time signal transmitted via a communication line by remote control from, for example, a gas company or a management company instead of the variable resistor 10. . 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.

[0042]

As described above, according to the first aspect of the present invention, the analog flow rate signal corresponding to the flow velocity of the fluid is integrated, that is, continuously integrated, even if the flow rate fluctuation occurs due to the pulsating flow. Thus, the fluctuation can be canceled and the influence of the pulsating flow can be removed. In addition, a fluid that passes an intermittent time based on a digital value obtained by sampling an analog integrated value signal corresponding to the integrated value of the analog flow rate signal every time a predetermined time longer than the period of the pulsating flow has elapsed since the drive of the flow rate sensor was started. By measuring the passing flow rate, it is possible to obtain the accurate flow rate of the fluid without the influence of the pulsating flow passing within the intermittent time by one sampling, without lowering the flow rate measurement accuracy, A flow measurement device capable of further reducing power consumption can be obtained.

According to the second aspect of the present invention, the counting means for counting the predetermined time can be used for counting the fixed time, so that a flow rate measuring device with reduced cost can be obtained.

According to the third aspect of the invention, for example, when the rotation cycle of the gas heat pump, which is one of the causes of the pulsating flow, is known in advance, the predetermined time is determined by the predetermined time setting means based on the rotation cycle. If the cycle of the pulsating flow is set, the fluctuation of the pulsating flow can be completely canceled by integrating one cycle. Moreover, when a pulsating flow having a period shorter than the maximum period of the pulsating flow is generated, a predetermined time is set according to the short period without setting the predetermined period for the maximum period of the pulsating flow, so that wasteful power is consumed. Since the consumption can be reduced, it is possible to obtain a flow measurement device capable of reducing the power consumption without further lowering the flow measurement accuracy.

According to the fourth aspect of the present invention, for example, a predetermined operation is performed by a remote operation from within a gas company or a management company that grasps the use condition of the gas heat pump which is one of the causes of the pulsating flow. Since the time can be set, an employee of the gas company or the management company can save time and effort to go to the place where the flow rate measuring device is installed, and can obtain a flow rate measuring device with reduced cost.

According to the fifth aspect of the present invention, even if the flow rate fluctuation occurs due to the pulsating flow, the fluctuation amount is canceled by integrating the analog flow velocity signal corresponding to the flow rate of the fuel gas, that is, continuously integrating the analog flow rate signal. , Eliminates the effects of pulsating flow. In addition, since the accurate flow rate of the fuel gas without the influence of the pulsating flow passing in the intermittent time can be obtained by one sampling, the power consumption can be further reduced without lowering the flow rate measurement accuracy. It is possible to obtain a flow measurement device capable of reducing the amount.

According to the sixth aspect of the present invention, by reducing wasteful power consumption, the accurate flow rate measured by the flow rate measuring device can be further reduced without lowering the flow rate measurement accuracy. Since the flow rate can be integrated and displayed, it is possible to obtain an electronic flow meter capable of accurately integrating and displaying the flow usage amount by reducing the error of the flow rate even if the power consumption is reduced. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration diagram of a flow measuring device and an electronic flow meter of the present invention.

FIG. 2 is a diagram showing an embodiment of an electronic flow meter incorporating the flow measurement device of the present invention.

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

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

FIG. 5 is a time chart for explaining the operation of an electronic gas meter incorporating the flow rate measuring device of FIG. 2;

FIG. 6 is a time chart showing an analog flow velocity signal and an analog integrated value signal when there is a flow rate.

FIG. 7 is a time chart showing an analog flow velocity signal and an analog integrated value signal when there is no flow rate.

FIG. 8 is a flowchart illustrating a processing procedure of a CPU in FIG. 2;

FIG. 9 is a diagram for explaining a problem of a conventional flow measuring device and an electronic flow meter.

FIG. 10 is a time chart for explaining a conventional countermeasure for pulsating flow.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow rate sensor (micro flow sensor) 5a-1 Driving means (CPU) 7 Integrating means (integrating circuit) 8 Digital converting means (A / D converter) 10 Predetermined time setting means 5a-2 Flow rate integrating means (CPU) 9 Display Means (display)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G08C 19/00 G08C 19/00 N (72) Inventor Ikko Ikko 1-5-20 Kaigan, Minato-ku, Tokyo No. Tokyo Gas Co., Ltd. (72) Inventor Minoru Seto 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Kenchi Kobayashi 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas In-house F term (reference) 2F030 CA10 CB09 CC13 CE02 CE04 CE07 CE09 CE25 CE32 2F031 AE07 AF04 2F035 EA05 EA08 EA09 GA02 2F073 AA16 AA40 AB01 BB04 BC01 CC07 CD00 DD02 DE00 EE16

Claims (6)

[Claims] 1. A flow rate sensor for outputting an analog flow rate signal corresponding to a flow rate of a fluid in a flow path, a driving unit for driving the flow rate sensor intermittently for a predetermined time, and an analog flow rate signal output by the flow rate sensor. Integrate and
Integrating means for outputting an analog integrated value signal corresponding to the integrated value; and sampling the analog integrated value signal every time a predetermined time longer than the period of the pulsating flow has elapsed since the drive for a predetermined time is started by the driving means. A digital conversion means for digitally converting the sampled analog integrated value signal, wherein the fluid passing through the flow path within the intermittent time based on the digital value of the analog integrated value signal converted by the digital converting means A flow rate measuring device characterized by measuring a passing flow rate of a fluid. 2. The flow measurement device according to claim 1, wherein the predetermined time is equal to the predetermined time. 3. The flow rate measuring device according to claim 2, wherein said driving means has a predetermined time setting means for resetting said predetermined time. 4. The flow rate measuring device according to claim 3, wherein the predetermined time setting means resets the predetermined time according to a predetermined time signal transmitted via an external communication line. 5. The flow measuring device according to claim 1, wherein the fluid is a fuel gas supplied to a gas combustor. 6. A flow rate measuring device according to claim 1, wherein the flow rate integrating device integrates a flow rate of the fluid passing through the intermittent time measured by the flow rate measuring device. Display means for displaying the integrated flow rate.