JP2003270009A - Method for measuring and displaying flow rate and flowmeter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a display a with smooth variation in accordance with an actual condition in use. <P>SOLUTION: To achieve the above mentioned purpose, while measuring and sampling with prescribed periods T1..., and repeating to integrate the flow rates up to next sampling points through the elapsed time based on the sampled measurement values Q1..., in order to display an integrated value, the amount of integration which is obtained from the measurement values Q1... at each sampling cycle and the periods T1... up to the next sampling points, is converted into a unit flow rate ΔQ which is the flow rate per a unit period Δt dividing the sampling points, and the unit flow rate ΔQ is integrated to a current total amount of integration ΣQ at every time when the unit period Δt elapses up to the next sampling point, and the amount of flow rate display is increased by a unit of display at every time when a variation of the unit of display occurs in the total amount of integration ΣQ. <P>COPYRIGHT: (C)2003,JPO

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 and displaying method and a flow meter used for the method, and is used for gas or tap water, for example.

[0002]

2. Description of the Related Art For example, a flow meter for measuring the actual amount of gas used is maintenance-free and has a service life of about 10 years, but it is an electric device having a power supply for driving and automatic management. In the current flowmeters, the power supply voltage is kept as small as 3V, and the flammability of gas is taken into consideration.
Therefore, power saving is a big problem, and one measure is to measure the flow rate only in a predetermined cycle to integrate the actual usage amount. Specifically, the measurement value of each time is sampled, and the integration of the measurement value is repeated with the lapse of time until the next sampling time. The actual usage amount obtained in this way, that is, the total integrated amount is increased and displayed each time there is a change in a predetermined display unit, and is used for confirmation of the usage status by the user and management of the gas supplier.

[0003]

However, in such a measuring method, even if the same flow rate is used, the following integrated amount is displayed based on the measured value at the previous sampling time. The accumulated amount at the time of the accumulated display based on the measurement value measured at the sampling point may have a difference for multiple display units. Although it is in a state of increasing at a constant rate in proportion to the
The display becomes unnatural because the jump changes more than one step. Such a phenomenon is more likely to occur as the sampling period is lengthened to save power, and the discontinuous state of display increases. In particular, in the numerical display, intermediate numbers are skipped by that amount, and it is easy for the user to feel discomfort and distrust.

An object of the present invention is to provide a flow rate measuring and displaying method capable of displaying with a smooth change according to an actual use state and a flow meter used for the method.

[0005]

In order to achieve the above-mentioned object, a flow rate measuring and displaying method of the present invention measures a flow rate of a target fluid at a predetermined cycle and samples the flow rate. While repeatedly integrating the flow rate until the next sampling time, while displaying the integrated value, the integrated amount obtained from the measured value sampled at each time and the time to the next sampling time, Converted to a unit flow rate per unit time divided up to the next sampling time, and each time the unit time elapses until the next sampling time, while adding the unit flow rate to the current total integrated amount, the total integrated amount Each time there is a change in the display unit, the main feature is to increase the display amount of the flow rate by the display unit.

In such a configuration, the flow rate of the target fluid is simply measured in a predetermined cycle, and the flow rate up to the next sampling time is repeatedly integrated with the measured value at the previous sampling time. The total flow rate is integrated and displayed, but the integrated flow rate is converted to a unit flow rate per unit time divided up to the next sampling time, so the unit flow rate is equal to the display unit depending on the number of divisions,
It can be reduced to an integer less than that, and each time the unit time elapses, the unit flow rate is added to the current total integrated amount, and the flow rate changes each time the total integrated amount changes by the displayed unit. By increasing the display amount of the display unit by the display unit, it is possible to shift to the next sampling time while displaying the display unit without skipping even one stage.

Here, if the unit time is set so that the sampling cycle is also an integer fraction, the final time point at which the integration for each unit time based on the measured value at the previous sampling time point ends coincides with the next sampling time point. Therefore, as long as there is no change in the flow rate, the integrated display based on the measured values by periodic sampling will change smoothly by the display unit with the passage of time. It is possible to avoid this.

As a flow meter for achieving the above method, a measuring means for measuring the flow rate of a target fluid and sampling at a predetermined cycle, and a measurement value previously sampled by this measuring means Integration means for integrating the flow rate during the period from the sampling time to
Conversion means for converting the integrated amount integrated by the integrating means into a unit flow rate per unit time obtained by dividing the time from the previous sampling time point to the next sampling time point, and the unit time set at each sampling time point Each time, the total flow amount is repeatedly calculated by adding up the unit flow rate to obtain the total integrated amount, and the flow rate is displayed each time the integrated amount accumulated by this total integrating unit changes by the displayed unit. The main feature is that it is provided with a display means for increasing the amount, and the integrated display of the flow rate having the above features can be automatically and stably performed for a long period of time with high accuracy.

In a further configuration in which the sampling cycle of the measuring means is shortened in accordance with the increase of the flow rate, even if the flow rate drops for a short time in the integration state where the flow rate is high, it is integrated with the measured value of the high flow rate. Since this leads to an integration error, shortening the sampling cycle makes it possible to catch flow rate changes early and suppress the integration error to a small value.

As described above, even when the sampling cycle is not constant, when the monitored result is changed from the previously sampled measurement value, the unit flow rate is obtained from the changed measurement value and the next sampling is performed. There is no problem if you add up to the point.

In particular, if a plurality of sampling cycles to be adopted are set to a time period that can be divided by the unit time, even if a uniform unit time is adopted for various cycles, the integration method based on the unit flow rate obtained thereby The above characteristics of are not impaired. It should be noted that depending on the size of the cycle, if the unit flow rate is equal to or smaller than the display unit by 1 / integral, a similar unit characteristic is not impaired even when different unit times are set.

In the flowmeter having the main characteristics, when the sampling cycle of the measuring means exceeds the minimum cycle by a predetermined time, the control means measures the flow rate at a cycle shorter than the sampling cycle at that time and samples first. If there is a change from the measured value that was previously sampled, and if it is changing from the measured value that was previously sampled, set the sampling cycle corresponding to that changed measured value to obtain the unit flow rate and In a further configuration, the measured value is sampled at a cycle according to the flow rate to suppress the integration error, and the actual flow rate is adjusted by integrating the flow rate at the unit time and unit flow rate corresponding to the cycle. Smooth integration display is possible.

Further objects and features of the invention will be apparent from the following detailed description and drawings. The respective features of the present invention can be employed alone or in combination in various combinations as much as possible.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 to provide an understanding of the present invention.
The following description shows specific examples of the present invention, and does not limit the description of the claims.

In the present embodiment, as shown in FIG. 1, gas is supplied to users such as households to use gas appliances such as a stove 1 and hot water supply equipment 2, heating equipment 3 and other gas equipment. It is an example of the case of the flow meter 4 for detecting the gas usage amount in the case. However, the present invention is not limited to this, and is effective when applied to all cases in which tap water and other fluids are supplied and used, and both of them belong to the scope of the present invention.

As shown in FIG. 1, the flowmeter 4 of the present embodiment has a measuring member 6 for indirectly detecting a flow rate in a gas supply channel 5 and a shutoff valve 7 for shutting off the channel 5. The flow rate detecting means 8 is provided, and the flow rate of the target fluid is measured by the measuring member 6 in a predetermined cycle and sampled, and the flow rate up to the next sampling time is integrated by the sampled measurement value repeatedly over time. However, the integrated value is displayed on the display unit 12 which is integral with or separate from the measuring unit 11. In addition to this, or separately, the information is transmitted to the administrator side through the line with the administrator side or the wireless transmission / reception unit 13 for the management. Although not shown, this management also includes pressure information of the target fluid, and flow rate detection and pressure detection are also performed in response to a request from the administrator.

The measuring member 6 has, for example, a pair of ultrasonic transducers 6a and 6b for transmitting and receiving ultrasonic waves with a target fluid sandwiched between them, the flow rate detecting means 8, a driving transmitting section 10a, and an amplifying receiving section 10b. And the ultrasonic transducer 6a on the downstream side of the gas flow which is the target fluid flowing in the direction indicated by the arrow 114 by the flow rate detecting means 8 connected to the flow rate detecting means 8 via the switching means 10c for switching the transmission / reception direction. Arrival time from when the ultrasonic wave is transmitted toward the ultrasonic transducer 6b on the upstream side, and when the ultrasonic wave is transmitted from the ultrasonic transducer 6b on the upstream side to the ultrasonic transducer 6a on the downstream side. The difference from the arrival time is measured, and the measured value is converted into the measured value of the flow rate of the gas flow to detect the flow rate. Actually, by summing up the arrival times of the ultrasonic waves when the ultrasonic waves are transmitted a plurality of times, it is possible to deal with the difficulty in handling one arrival time which is extremely small. Further, since the target fluid is a gas and is flammable, it is necessary to keep the power source of the flowmeter 4 small, for example, about 3 V to ensure safety, and to save power as much as possible to withstand maintenance-free use for about 10 years. Therefore, under conditions where the flow rate is small and it is difficult to obtain a time difference between the upstream transmission and the downstream transmission and accurate measurement is difficult, the number of ultrasonic wave transmissions and receptions at the time of measurement is increased to deal with it. Reduce the number of times. In addition to this, the flow rate is measured at a predetermined cycle, the measurement value is sampled, and the flow rate is integrated according to the elapsed time from this measurement value to the next sampling time to obtain the usage flow rate and the like. . Moreover, the sampling cycle is shortened when the flow rate is large and an error is likely to occur in the integration, but it is lengthened when the flow rate is small.

FIG. 2 shows an example of the relationship between the flow rate Q and the number of times of transmission and reception of ultrasonic waves. The number of times of transmission and reception N1 set corresponding to the flow rate Q1 and the number of transmission and reception N3 set corresponding to the flow rate Q3 are, for example, Have a gap of several times. The flow rate detecting means 8 switches the switching means 10c according to the measurement signal S1 shown in FIG.
The drive signal S2 is alternately applied to the ultrasonic transducers 6a and 6b by the set number N via the. One driven by the drive signal S2 of the ultrasonic transducers 6a and 6b repeatedly transmits ultrasonic waves toward the other for the set number N, and the output of the other receiving this is monitored by the measuring means 14. This monitored output is the waveform data S3 as in the example of the transmission / reception operation shown in FIG.

In the figure, an example in which the number of transmissions and receptions is set to 3 is shown for the sake of simplicity. The data S3 in this transmission / reception operation example is schematically shown in an enlarged time width with respect to the transmission time width of the drive signal S2 for easy understanding, but there is a noise waveform before and after the data S3 portion, and the data S3 portion. Although the noise waveform that follows is attenuated, a so-called trailing state occurs, which remains for a relatively long time. Therefore, for accurate measurement, the next measurement is performed at the time after the noise waveform is attenuated.
Specifically, as shown in the transmission / reception operation example of FIG. 4, a waiting time tm until the trailing of the drive signal S2 is attenuated to a predetermined state is set for the measurement signal S1. In addition, when the transmission / reception operation is repeated multiple times in a short time, the data S
The partial reception waveform of 3 tends to gradually increase as shown in FIG. 4, and the reception start time point is not clear in relation to the noise waveform. Therefore, a time point ts, which is a time point when the waveform for the number of times of reception is traced back from the zero-cross time point te of the waveform at the time of the last reception time when the reception waveform becomes large, is determined as the reception start time point, and the time between them is treated as the total reception time.

FIG. 3 shows an example of the relationship between the flow rate Q and the cycle T at which the flow rate is measured and sampled by the ultrasonic wave transmission / reception operation, and corresponds to the cycle T1 and the flow rate Q3 set corresponding to the flow rate Q1. The cycle T3 set by the above setting is set to have a difference of less than 10 times. Therefore, the measuring means 14 sets the measurement signal S1 in a cycle according to the flow rate Q as shown in FIG.

In FIG. 4, the flow rate Q is Q for simplicity of explanation.
3, Q2, Q1, and Q2 are simply changed, and the sampling cycle T3 and the number of transmissions / receptions N with respect to the flow rate Q3 are shown.
3 is the sampling cycle T2 with respect to the flow rate Q2 and the number of transmissions / receptions N2 is the sampling cycle T1 with respect to the flow rate Q1.
The number of times of sending and receiving N1, the sampling cycle T2 and the number of times of sending and receiving N2 are sequentially set for the flow rate Q2 in accordance with the change of the flow rate. Where Q3>Q2> Q1 and
T3 <T2 <T1 and N3 <N2 <N1.

Basically, in the present invention, it does not matter what kind of measuring member 6 is used as the flow rate detecting means 8 and what kind of detecting method is used, and it is not necessary to determine the measuring value of the periodic flow rate. The present invention can be applied to all flowmeters of the type in which the flow rate is integrated based on the flow rate, and the target fluid and its intended use and supply purpose are not particularly limited.

The flow meter 4 of the present embodiment measures the flow rate of the target fluid, that is, the flow rate at each time, for example, Q1, Q2, Q3, etc. at a predetermined cycle T and samples them, and the sampled measured values Q1 and Q2. , Q3, the accumulated value is displayed while repeating the accumulation of the flow rate until the next sampling time, and in particular, the measured values Q1, Q2, Q3 sampled at each time and the next sampling time are displayed. The integrated amount obtained from the time is converted into a unit flow rate ΔQ1, ΔQ2, ΔQ3 per unit time Δt obtained by dividing the time until the next sampling time, and each time the unit time Δt elapses until the next sampling time, the unit is changed. Flow rate ΔQ1, ΔQ2, and ΔQ3 minutes are now the total integrated amount ΣQ
Each time the total integrated amount ΣQ changes by the display unit, the display amount of the flow rate is increased by the display unit.

In the example of the flow rate Q3 in FIG. 4, since the sampling cycle time is T3 and the unit flow rate is ΔQ3, each time the unit time Δt elapses from the previous measurement time point to the next measurement time point, ΔQ3 is added. The stepwise integration of
At the time of the next sampling, (T3 / Δt) × ΔQ3 minutes can be smoothly integrated, and this is continued while the flow rate Q3 continues. Similarly, while the flow rate is Q2, (T2 / Δt) × ΔQ between the previous sampling time point and the next sampling time point in a sampling period T2 commensurate with the flow rate Q2.
The integration for 2 minutes can be performed smoothly, and while the flow rate is Q1, in the sampling period T1 corresponding thereto, between the previous sampling time point and the next sampling time point (T3 / Δt)
× ΔQ3 minutes can be smoothly integrated.

In this way, the flow rate of the target fluid is set to the predetermined period T
Just by measuring, the measured value Q at the previous sampling time
The total flow rate is integrated by displaying the total flow rate by repeating the integration of the flow rate up to the next sampling time with 1 or Q2, Q3, and displaying it. Since it is converted into the unit flow rate ΔQ1, ΔQ2, and ΔQ3 per time, the unit flow rate ΔQ1, ΔQ2, and ΔQ3 can be equal to the display unit or a whole number less than that depending on the number of divisions at that time. , Unit flow rate ΔQ1 each time unit time elapses
By incrementing the amount of ΔQ2 or ΔQ3 into the current total integrated amount ΣQ and increasing the display amount of the flow rate by the display unit each time the total integrated amount ΣQ changes by the display unit,
It is possible to shift to the next sampling time while displaying one display unit without skipping even one display unit. The display is the same for both graphs and numerical values as long as it shows the change in quantity. Taking a numerical value as an example, if the display unit is 1 cc, select a unit flow rate of 1 cc equal to that, or select a unit time Δt that is 0.5 cc, 0.01 cc, 0.05 cc, etc. If the unit flow rates ΔQ3, ΔQ2, and ΔQ1 are calculated, the integrated flow rate ΣQ is integrated and displayed so that the integrated flow rate ΣQ continuously changes as shown in FIG. 4 during the integrated display at the same flow rate Q. can do.

Here, if both the unit time and Δt are selected so that the sampling cycle T is an integer fraction, the unit time Δ at the same flow rate based on the measured value at the previous sampling time.
The final time point at which the integration for each t ends is the same as the next sampling start time point as shown in FIG. Therefore, as long as there is no change in the flow rate Q, a display state is obtained in which the integrated display based on the measured values by periodic sampling changes smoothly in display units over time, and the numerical values fluctuate even if they are displayed in numerical steps. This can be avoided, smooth display without sudden changes as shown in FIG. 4 can be performed, and the numerical value does not jump even in the numerical value display.

In order to achieve such a method, the flow rate detecting means 8 of the present embodiment uses the measuring means 14 for repeating the measurement and sampling of the flow rate of the target fluid at a predetermined cycle, and the measuring means 14. An integrating means 15 for integrating the flow rate Q between the previously sampled measured values Q3, Q2, Q1 and the like and the time until the next sampling time, that is, the period T3, T2, T1 and the like, and the integrating means 15 The unit time Δ obtained by dividing the integrated amount by dividing the time from the previous sampling time to the next sampling time.
The conversion means 16 for converting into the unit flow rate ΔQ per t, and every time the unit time Δt set at each sampling time elapses, the unit flow rate ΔQ corresponding to the unit time Δt is repeatedly accumulated to repeat the total integration amount. The total integration means 17 for obtaining ΣQ is provided, and each time the total integration amount ΣQ integrated by the total integration means 17 changes by the display unit, the flow rate display on the display unit 12 is increased by one display unit. It should be noted that the sampling period T, which is set and handled in advance, the number N of ultrasonic wave transmissions and receptions, the unit time Δt, the unit flow rate ΔQ, and the like are input from the input unit 18. Also, these can be changed later. As a result, the integrated display method as described above can be automatically and stably achieved for a long period of time with high accuracy.

Further, the flow rate detecting means 8 operates in conjunction with the control means 21, and the control means 21 determines the sampling periods T1, T2, T3, etc. corresponding to the measured flow rates Q1, Q2, Q3, etc. , Number of transmissions / receptions N1, N2, N3
Are automatically set, and as described above, the cycle T is shortened according to the increase of the flow rate Q, and the number of times of transmission and reception is increased so that the flow rate can be measured with high accuracy.

As described above, even when the sampling period T is not constant according to the flow rate Q, when the result of monitoring the measured value changes from the previously sampled measured value, t3, t5, etc. in FIG. There is no problem because the unit flow rate is obtained from the changed measured value and the integration is performed until the next sampling time. For example, if the time point of t3 is taken as an example, it can be dealt with by switching from the integration of (T3 / Δt) × ΔQ3 minutes to the integration of (T2 / Δt) × ΔQ2.

In particular, the plurality of sampling periods T adopted
If 1, T2, T3, etc. are set so that they can be divided by the unit time Δt, even if a uniform unit time Δt is adopted for each cycle T, the continuation of the integration with the unit flow rate ΔQ can be obtained. The sexual characteristics are not impaired. However, since the unit flow rate ΔQ fluctuates depending on the difference in the periods T1, T2, T3, it is necessary to take care not to impair the relationship of the unit flow rate ΔQ with respect to the display unit. In addition,
Different cycles T1, T provided that the unit flow rate ΔQ is equal to or less than the display unit
Even when different unit times Δt are set for 2 and T3, the above characteristics are not impaired.

When the sampling period T of the measuring unit 14 exceeds the minimum period by a predetermined time, the control unit 21 has the periods T2 and T1 with respect to the period T3 in the example of FIG. As shown by a broken line in FIG. 4 in a cycle shorter than T2 or T1, for example, cycle T3,
Measured flow rate and sampled values Q3 and Q previously sampled
If there is a change from 2, the measured value Q2 or Q1 previously sampled is changed, and thereafter, the sampling cycle corresponding to the changed measured value is set to obtain the unit flow rate ΔQ, and Be sure to perform integration up to the sampling point.

As a result, the measured value Q is sampled at the cycle T corresponding to the flow rate and the integration error is suppressed, while the unit time Δt corresponding to the cycle T and the flow rate at the unit flow rate ΔQ are integrated so that the actual flow rate is determined. The smooth integrated display is possible. In the example shown in FIG. 4, the cycle T2 set according to the flow rate,
Except at the time of sampling at T1, the flow rate Q is measured, sampled and monitored at the minimum period T1 as shown by the broken line. Thus, in the example shown in FIG. 4, when the operation is performed only by normal sampling, the change from the flow rate Q1 to the flow rate Q2 at t6 is the flow rate Q1.
The measurement can be performed only at the next sampling time t9 in the cycle T2 corresponding to 2, but it can be detected early by the monitor by sampling at the time t7, and the sampling cycle corresponding to the changed flow rate Q2 thereafter. By setting T2 and the number of times of transmission / reception N2, correct integration can be started early.

[0033]

According to the present invention, by simply measuring the flow rate of a target fluid at a predetermined cycle, the flow rate up to the next sampling time can be integrated with the measured value at the previous sampling time. The total flow rate is repeatedly accumulated and displayed, but this accumulated amount is converted into the unit flow rate per unit time divided up to the next sampling time.Therefore, is the unit flow rate equal to the display unit depending on the number of divisions? Also, it can be reduced to an integer less than that, and each time the unit time elapses, the unit flow amount is added to the current total integrated amount, and the total integrated amount changes each time the display unit changes, By increasing the display amount of flow rate by the display unit,
It is possible to shift to the next sampling time while displaying one display unit without skipping even one display unit.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a flow meter according to an embodiment of the present invention.

FIG. 2 is a graph schematically showing the relationship between the flow rate and the number of times of transmission and reception adopted by the device of FIG.

FIG. 3 is a graph schematically showing a relationship between a flow rate adopted by the apparatus of FIG. 1 and a cycle of measuring and sampling the flow rate.

FIG. 4 is a time chart showing operations of flow rate measurement and integration performed by the apparatus of FIG.

[Explanation of symbols]

4 flow meter 5 channels 6 measuring members 8 Flow rate detection means 11 Measuring section 12 Display 14 Measuring means 15 means of accumulation 16 Conversion means 17 Total accumulation means 18 Input section 21 Control means

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2F030 CA03 CC02 CC13 CE04 CE25                       CE28                 2F031 AF04

Claims (6)

[Claims] 1. An integrated value is displayed by repeatedly measuring the flow rate of a target fluid at a predetermined cycle and sampling, and repeatedly integrating the flow rate up to the next sampling time with the sampled measured value. This is a method of measuring and displaying the flow rate, in which the integrated amount obtained from the measurement value sampled each time and the time until the next sampling time is converted to a unit flow rate per unit time divided up to the next sampling time. Whenever the unit time elapses until the next sampling point, the unit flow rate is added to the current total integrated amount, and the display unit of the flow rate is displayed each time the total integrated amount changes by the display unit. A method of measuring and displaying the flow rate, characterized by increasing the number of minutes. 2. The method for measuring and displaying a flow rate according to claim 1, wherein the sampling cycle is shortened as the flow rate increases. 3. The method according to claim 2, wherein when the monitored result has changed from the previously sampled measurement value, the unit flow rate is obtained from the changed measurement value and integration is performed until the next sampling time. How to measure and display the stated flow rate. 4. A measuring unit that repeats measuring and sampling a flow rate of a target fluid in a predetermined cycle, and a flow rate between a measured value previously sampled by this measuring unit and a time until the next sampling time point. And a converting means for converting the integrated amount integrated by the integrating means into a unit flow rate per unit time obtained by dividing the time from the previous sampling time point to the next sampling time point, and at each sampling time point. Every time the set unit time elapses, the total amount of accumulated flow obtained by repeating the totalization of the unit flow rate corresponding to the unit time and the total amount accumulated by the total unit are the display unit amount. A flow meter, comprising: a display unit for increasing the display amount of the flow rate each time it changes. 5. A flow meter, comprising: a control unit that shortens a sampling cycle of the measuring unit according to an increase in the flow rate. 6. The control means, when the sampling cycle of the measuring means exceeds the minimum cycle for a predetermined time, measures the flow rate at a cycle shorter than the sampling cycle at that time and changes the measured value from the previously sampled measurement value. If there is a change from the previously sampled measurement value, set the sampling period corresponding to the changed measurement value to obtain the unit flow rate, and integrate until the next sampling time. Item 6. The flowmeter according to any one of items 4 and 5.