JP3344847B2 - Fluidic gas meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures a flow rate in an oscillation region of a fluid oscillation device based on fluid vibration of the fluid oscillation device, and measures a flow rate smaller than the oscillation region by a flow sensor. More particularly, the present invention relates to a fluidic gas meter having means for reducing a measurement error due to a gas pressure fluctuation.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 3-96817 discloses a fluid flow meter for gas which is convenient for use in a gas meter.

This fluidic flow meter includes a fluidic oscillation element for measuring a flow rate in a medium to large flow rate range, and a thermal flow sensor for measuring a flow rate in a small flow rate range.

In a fluid oscillation device, a flow path enlarged portion is formed by a pair of side walls on a downstream side of a nozzle for generating a jet flow, and a fluid that has passed through the nozzle is separated by a return guide provided outside the side walls. Forming a pair of feedback passages that guide the nozzle to the nozzle outlet side along the outside of the side wall, utilizing fluid vibration in which the fluid passing through the nozzle alternately flows through the pair of feedback passages, based on the frequency of this fluid vibration To measure the fluid flow.

[0005] Fluid vibration of the fluid oscillation element is converted into an electric signal by a pressure sensor and is electrically processed. The flow sensor is provided at a nozzle of the fluid oscillation element, and generates an electric signal corresponding to the flow velocity of the nozzle. It is driven intermittently at 6-second intervals to perform intermittent measurement.

The fluidic flow meter for gas measures the flow rate based on the fluid vibration of the fluid oscillation element when the period of the fluid oscillation of the fluid oscillation element is equal to or less than a predetermined value, that is, when the flow rate is equal to or greater than the fixed value. When the cycle of the fluid vibration exceeds another predetermined value, that is, when the flow rate is less than a certain value, the pressure sensor and the flow sensor are changed according to the cycle of the fluid vibration so as to measure the flow rate based on the signal of the flow sensor. I try to switch. The difference between the two constant values is so-called hysteresis.

Further, within a predetermined flow rate range, the flow rate is measured by both the fluidic oscillation element and the flow sensor, and the flow sensor is calibrated based on the signal of the fluidic oscillation element, that is, the pressure sensor. I have.

[0008]

When the fluid meter for gas is used in a gas meter, the fluid vibration of the fluid oscillation element is detected when the pressure of the supplied gas changes pulsatingly due to a load change. In some cases, an electrical signal that should be output from the pressure sensor is missing or a whisker-like signal is superimposed excessively, which causes an error in the integrated flow rate.

[0009] When "pulse dropout" in which an electric signal is lost occurs, the integrated flow rate becomes excessively small, and when "whiskers" enter, overintegration is performed by an amount corresponding to the electric pulse, and the integrated flowrate becomes excessively large. In addition, if there is "missing pulse", the period of the electric signal of the pressure sensor at that time becomes abnormally large, and the sensor is unnecessarily switched from the pressure sensor to the flow sensor.

FIG. 14 shows such a "pulse missing".
It is a figure explaining the state at the time of doing. As shown in FIG.
And the pulse P of the electric signal of the pressure sensor₁, P_Two…,
P₆, P ₇Out of which pulse P_FourLack
And the pulse P_ThreeAfter a certain period of time, (b) in FIG.
The flow sensor drive signal is output as
The sensor is switched from the pressure sensor to the flow sensor.

When the pressure of the supply gas changes in a pulsating manner, the "pulse missing" occurs because when the amplitude of the electric signal of the pressure sensor changes due to the fluctuation of the gas pressure, the electric signal of the pressure sensor changes its waveform. This is because the pulse of the square wave is temporarily missing due to the loss of the threshold value of the shaping circuit.

This mechanism will be described with reference to FIG. In FIG. 3A, a is an output electric signal of the pressure sensor, which changes substantially in a sine wave shape. V ₁ and V ₂ are threshold values of the waveform shaping circuit. When the voltage of the electric signal A of the pressure sensor rises and exceeds the threshold value V ₁ , the output of the waveform shaping circuit becomes high level “H”. The output of the waveform shaping circuit when the voltage of the electric signal b of the pressure sensor becomes the threshold value V ₂ less descends becomes low "L".

[0013] Thus, the output electrical signal Yi of the pressure sensor becomes a square wave as shown is shaped by a waveform shaping circuit in FIG. (B), as in the case pulse P ₄ described in FIG. 14
Missing occurs "missing pulses", a predetermined time after the after the pulse P ₃ is switched are flow sensor drive signal as shown in the diagram (c) is output, the flow rate measuring sensor is a flow sensor from a pressure sensor Can be

As is apparent from FIG. 15, the pulse P ₄ which should occur originally is missing due to the relationship between the amplitude of the electric signal and the threshold values V ₁ and V _{2 in} FIG. Can be understood.

The square wave signal obtained by converting the fluid vibration of the fluid oscillation element into an electric signal by the pressure sensor is not limited to the "pulse missing" in which the pulse is lost as described above. It can also produce so-called "whiskers" where extra pulses occur.

[0016] When "pulse missing" occurs, the integrated flow rate of the gas meter becomes too small, and when "whiskers" occur, the integrated flow rate becomes too large. Since the flow sensor intermittently operates at intervals of several seconds and performs intermittent measurement, if the period of the electric signal of the pressure sensor fluctuates due to supply pressure fluctuation, the pressure sensor and the flow sensor are frequently switched, and the integration error is reduced. There was a problem that it occurred.

FIG. 16 shows a state in which a large supply pressure fluctuation is superimposed while the used gas flow rate is gradually changing with time. In the figure, what is indicated by a virtual line b is
Slow temporal change near the time average of the used gas flow rate,
The curve indicated by the symbol c is the actual flow rate, which fluctuates greatly under the influence of the supply pressure fluctuation.

[0018] Q _D is a toggle threshold is a measurement sensor above which the flow rate is switched to the pressure sensor from the flow sensor (i.e. fluidic oscillator), an electrical pressure sensor 10 corresponding to the threshold Q _D The period of the signal is T _D.

[0019] Q _S in which the following switching between the measuring sensor will flow is switched to the flow sensor from the pressure sensor (i.e. a fluidic oscillator) threshold, the pressure sensor 10 corresponding to the threshold flow rate Q _S The period of the electric signal is T _S.

[0020] Incidentally, the difference between the two thresholds Q _D and Q _S for switching the measuring sensor is a so-called hysteresis. The hysteresis is expressed in a flow rate threshold Q _D and Q _S (hysteresis) a = Q _D -Q _S, is expressed by the threshold T _D and T _S of the period of the electrical signal of the pressure sensor 10 ( (Hysteresis) = T _S −T _D.

As is apparent from FIG. 16, when the flow rate Q changes as indicated by the symbol C due to the change in the supply gas pressure, the flow rate Q changes as compared with the flow rate indicated by the symbol B where the gas pressure does not fluctuate.
An unnecessary flow sensor drive signal E is output. At this time, as indicated by reference numeral, the measurement sensor is switched from the pressure sensor to the flow sensor.

FIG. 17 shows the switching of the pressure sensor signal, the flow sensor drive signal, and the measurement sensor when the gas pressure does not fluctuate and the gas flow rate changes slowly as shown by the curve B. , Compared to the case of FIG.
There is no unnecessary switching of measurement sensors.

As described above, in the related art, the switching of the sensor due to the fluctuation of the supply gas pressure is frequently performed, which causes an integration error. Therefore, an object of the present invention is to provide a fluidic gas meter that can solve these problems.

[0024]

In order to achieve the above object, a fluidic gas meter according to the first aspect of the present invention comprises a fluid sensor, wherein a fluid oscillation of the fluidic oscillating element is detected by an electric signal by a pressure sensor. And measures the flow rate in the medium to large flow rate range based on the electric signal, and also measures the flow rate based on the electric signal of the flow sensor (12) disposed in the nozzle (2) of the fluidic oscillation element (7). In a gas meter for measuring a flow rate in a flow rate range, the pressure sensor (1)
The cycle of the electric signal of 0) is successively compared based on a predetermined threshold coefficient to grasp a change tendency, and “pulse missing” and “whisker” in the electric signal of the pressure sensor (10) are determined according to the change tendency. And a flow sensor based on the calculated average period, calculating an average value of a plurality of (N) continuous periods of the pulse-complemented electric signal. A first sensor switching determination unit (23) for controlling the switching of (12), and when the period (T) of the electric signal of the pressure sensor (10) before pulse complementation is equal to or greater than a fixed value (Tover), The flow measurement sensor is changed from the pressure sensor (10) to the flow sensor (12).
And a second sensor switching determination unit (32) for performing switching control with priority.

In this fluidic gas meter, the period of the electric signal of the pressure sensor (10) according to the fluid vibration of the fluidic oscillation element (7) is successively compared based on a predetermined threshold coefficient. Thus, the change tendency of the cycle can be detected. "Pulse missing" according to the changing tendency of this cycle
And "beard" are complemented.

Then, an average value of a plurality of (N) consecutive periods of the electric signal thus pulse-complemented is calculated. The first sensor switching determination unit (23) sets the measurement sensor to the pressure sensor (10) or the flow sensor (1) based on the average value of the plurality (N) of cycles calculated in this manner.
Switch control to 2).

Further, the cycle (T) of the electric signal before pulse interpolation of the pressure sensor (10) is sequentially measured, and when this cycle (T) is equal to or greater than a fixed value (Tover), the second cycle is determined.
The sensor switching determination unit (29) preferentially switches and controls the flow rate measurement sensor from the pressure sensor (10) to the flow sensor (12).

In the fluidic gas meter according to the second aspect, the second sensor switching determination section (32) according to the first aspect of the present invention uses the pressure sensor (1)
When the first sensor switching determination unit (23) switches from the pressure sensor (10) to the flow sensor (12), the constant value (Tover) of the cycle of the electric signal when switching from the pressure sensor (0) to the flow sensor (12) is switched. Is set between 2 and 3 times the threshold value (T _S ) of the average period.

In this fluidic gas meter, the cycle of the electric signal of the pressure sensor (10) before pulse interpolation is measured one by one, and the cycle is equal to a threshold value (T _S ) of two.
If the number of times is equal to or more than three times, the second sensor switching determination unit (3
2) The measurement sensor is preferentially switched from the pressure sensor (10) to the flow sensor (12) and controlled.

According to the present invention, the gas flow rate becomes zero during the calculation of the average value of a plurality of (N) consecutive periods of the pulse-complemented electric signal, and It is preferable that the second sensor switching determination unit (32) promptly responds to the switching control of the measurement sensor even when the measurement stops halfway.

In the fluid gas meter according to the third aspect, the fluid vibration of the fluid oscillation element (7) is converted into an electric signal by the pressure sensor (10), and the flow rate in the middle to large flow area is determined based on the electric signal. And a flow meter for measuring a flow rate in a small flow rate range based on an electric signal of a flow sensor (12) disposed in a nozzle (2) of a fluidic oscillation element (7).
The cycle of the electric signal of 0) is successively compared based on a predetermined threshold coefficient to grasp a change tendency, and “pulse missing” and “whisker” in the electric signal of the pressure sensor (10) are determined according to the change tendency. And a flow sensor based on the calculated average period, calculating an average value of a plurality of (N) continuous periods of the pulse-complemented electric signal. The sum of the cycles of a plurality (n) of consecutive electric signals of the first sensor switching determination unit (23) that controls the switching of (12) and the pressure sensor (10) before pulse interpolation is constant ( A second sensor switching determination unit (32A) that switches and controls the flow measurement sensor from the pressure sensor (10) to the flow sensor (12) preferentially when T _a ) or more.

In this fluidic gas meter, the period of the electric signal of the pressure sensor (10) according to the fluid vibration of the fluidic oscillator (7) is successively compared based on a predetermined threshold coefficient. Thus, the change tendency of the cycle can be detected. "Pulse missing" in response to this cycle change tendency
And "beard" are complemented.

Then, an average value of a plurality of (N) consecutive periods of the electric signal thus complemented is calculated. The first sensor switching determination unit (23) controls to switch the measurement sensor to the pressure sensor (10) or the flow sensor (12) based on the calculated average value of the plurality of (N) cycles.

Further, if the sum of the cycles of a plurality (n) of the electric signals before the pulse complementation of the pressure sensor (10) is equal to or more than _a fixed value (T _a ), the second sensor switching determination unit ( 32A) uses a flow rate measuring sensor as a pressure sensor (10).
From the control to the flow sensor (12).

According to a fourth aspect of the present invention, in the fluidic gas meter according to the third aspect of the present invention, the number of periods when calculating the total of the continuous periods of the electric signal of the pressure sensor (10) before the pulse interpolation is performed. (N) is set to be equal to or less than the number (N) of cycles when calculating the average value of the continuous cycles of the pulse-complemented electric signals, and the continuation of the electric signals of the pressure sensor (10) before the pulse complement is performed. The constant value (T _a ) for comparing the total of the cycles is determined by the threshold value (T) of the average cycle when the first sensor switching determination unit (23) switches from the pressure sensor (10) to the flow sensor (12). _S ) and the product of the number of cycles (N) for calculating the average of successive cycles of the pulse-complemented electrical signal (T _S ×
N) It is characterized by the following.

In this fluidic gas meter, the total value of n consecutive periods of the electric signal of the pressure sensor (10) before pulse interpolation is determined by the threshold value (T _S ) and the plurality (N). When the value becomes equal to or more than _a constant value (T _a ) that is equal to or less than the product (T _S × N) of the pressure sensor, the second sensor switching determination unit (32A) controls the flow rate sensor to switch from the pressure sensor (10) to (12) I do.

According to the present invention, even if the gas flow rate becomes zero during the measurement of a plurality of (N) consecutive periods of the pulse-complemented electric signal, the second sensor switching determination unit (32A) ) Is preferable in that the switching of the measurement sensor is promptly controlled.

[0038]

In FIG. 2, 1 is an inlet, 2 is a nozzle, 3,
3 'is a side wall, 4 and 4' are feedback flow path inlets, 5 is a target located at the downstream central portion of the nozzle 2, 6 is an outlet, and 7 is an entire fluidic oscillator composed of an inlet 1 to an outlet 6. It is. Reference numeral 8 denotes a case main body for forming the fluidic oscillation element 7.

Reference numeral 10 denotes a pressure sensor composed of a piezoelectric film sensor, which detects fluid vibration of the fluid oscillation element guided by the pressure introducing passages 9 and 9 'and converts it into an electric signal.
Reference numeral 12 denotes a thermal type flow sensor arranged in the nozzle 2, which detects a flow speed which is increased by being throttled by the nozzle 2, and detects a flow speed (flow rate).
An analog electric signal proportional to is output every 6 seconds.

Reference numeral 11 denotes an amplifier for amplifying the electric signal of the pressure sensor 10, and reference numeral 13 denotes an A / D conversion circuit for converting an analog electric signal of the flow sensor 12 into electric pulses having a pulse number proportional to the flow rate (flow rate).

FIG. 2 shows a state where the lid of the fluid oscillation element 7 is removed for easy understanding.
The pressure sensor 10 for detecting the fluid vibration includes a pair of pressure introduction ports 14, 14 'opening to the feedback flow paths 4 and 4'.
One end of each of the pressure introduction passages 9 and 9 ′ communicates with the pressure sensor 10, and the other end of each of the pressure introduction passages 9 and 9 ′ communicates with a pair of pressure introduction ports 15 and 15 ′ of the pressure sensor 10.
Pulsating pressure due to fluid vibration is differentially applied to both sides of the polymer piezoelectric film 16.

The arrow A indicates the flow of gas flowing into the inlet 1 of the fluid oscillation element 7. In the block diagram of FIG. 1, reference numeral 17 denotes a waveform shaping circuit which converts an output of the amplifier 11 into a binarized square wave electric signal. Reference numeral 18 denotes a cycle measuring unit that measures the cycle of the output signal (square wave) of the waveform shaping circuit 17.

Reference numeral 19 denotes a change tendency judging section,
Are successively compared based on a predetermined threshold coefficient to detect a change tendency. Reference numeral 20 denotes a threshold coefficient memory for storing the threshold coefficient. Reference numeral 21 denotes a pulse complement unit that complements “missing pulse” and “whiskers” according to the change tendency detected by the change tendency determination unit 19.

Reference numeral 22 denotes an average period calculating unit, which is a pulse complementing unit 2
The average value of N consecutive periods of the electric signal complemented by 1 is calculated. Reference numeral 23 denotes a first sensor switching determination unit that switches between the pressure sensor 10 and the flow sensor 12 based on the average value of N cycles calculated by the average cycle calculation unit.

Reference numeral 24 denotes a flow sensor drive control circuit,
Of the flow sensor 12
When it is determined that the measurement is performed, the drive control of the flow sensor 12 is performed at short intervals at intervals of 6 seconds.

A pulse counter 25 counts the number of output pulses of the A / D conversion circuit 13 every 6 seconds. Reference numeral 26 denotes a first volume conversion unit, which converts the pulse of the pressure sensor 10 complemented by the pulse complement unit 21 by a pulse constant to convert the pulse into a volume. A second volume conversion unit 27 converts the count value of the pulse counter 25, that is, the number of pulses of the flow sensor 12 every 6 seconds, by a pulse constant to convert the volume into a volume.

Reference numeral 28 denotes the first sensor switching determination unit 2
3 and a change-over switch operated by a signal of a second sensor change-over judging unit, which will be described later, and the first volume conversion unit 2
6 and the output signal of the second volume conversion unit 27 are selected and input to the integration unit 29.

The integrating section 29 integrates the outputs of the first and second volume converting sections 26 and 27 selected by the changeover switch 28. The accumulated gas usage is displayed as a number on the display unit 30.

Reference numeral 31 denotes a sensor switching threshold value memory.
When the first sensor switching determination unit 23 switches the measurement sensor based on the average value of the N consecutive cycles calculated by the average period calculation unit 22, a threshold value serving as a reference for comparison is stored.

Reference numeral 32 denotes a second sensor switching determining unit which changes the period of the electric signal measured by the period measuring unit 18 by one period.
The value Tover stored in the Tover value memory 33
And a switch for switching the flow measurement sensor from the pressure sensor 10 to the flow sensor 12 when the period of the electric signal of the pressure sensor 10 (strictly speaking, the square wave output signal of the waveform shaping circuit 17) is equal to or longer than Tover. 28 is switched from the illustrated state.

Next, the operation of the first embodiment shown in FIG. 1 will be described. First, the pulse complement operation will be described in detail. When the pressure sensor 10 detects the fluid vibration of the fluidic oscillation element 7, the cycle is measured by the cycle measuring unit 18, and is sequentially compared based on the threshold coefficient stored in the threshold coefficient memory 20. The change tendency judging section 19 examines the change tendency of the cycle and determines one of the following three tendencies.

(1). When the relationship between the period T _n-1 cycle T _n and the immediately preceding that time is _{(3/2) T n-1 <} T n ... (1), the change trend of the period is "period increase" judge.

(2). When the relationship between the period T _n and the period T _n-1 immediately before that time is _{(2/3) T n-1 ≦} T n ≦ (3/2) T n-1 ... (2), the period of It is determined that the change tendency is “no cycle increase / decrease”.

(3). When the relationship between the period T _n-1 period T _n and the immediately preceding that time is _{(2/3) T n-1>} T n ... (3), when the change tendency of the period is "periodic decrease" judge.

[0055] In the above-mentioned (1) to (3), in the threshold coefficient is (3/2) and (2/3) for use in comparison with the period T _n, predetermined by the threshold It is stored in the value coefficient memory 20.

Then, when the change tendency of the cycle continuously shows "cycle increase" followed by "cycle decrease", it is determined that "pulse missing" has occurred, and "pulse missing" is complemented. In other words, the processing is performed by dividing a large cycle into two half cycles.

The concept of the process for complementing this "pulse missing" will be described below with reference to FIG. Period of fluidic electrical signal by the pressure sensor 10 the fluid vibration is shaped into a square wave by the waveform shaping circuit 17 detects the oscillation element 7, as shown in FIG. (A), the period following the period T _n T _{n + 1} and period T
_{n + 2} and (3/2) T _n <T _{n + 1} , so that “period increase” and subsequently T _{n + 1} > (3/2) T _{n + 2} , "Cycle decrease", it is determined that "pulse missing" has occurred in this case.

FIG. 11B shows a pulse complementing process performed because it is determined that the pulse is missing. The large cycle T _{n + 1} shown in FIG. _{n + 1} of 2
FIG. 9 shows a state in which the pulse is divided into a plurality of periods, and one pulse that is eventually insufficient is added and complemented.

Next, the concept of the "whiskers" determination and its complement processing will be described below with reference to FIG. Periodic electrical signal shaped into a rectangular wave by the waveform shaping circuit 17 the fluid vibration of the fluidic oscillator 7 is detected the pressure sensor 10 is, as shown in FIG. (A), following the period T _n, the period Continues with T _{n + 1} , period T _{n + 2} , and period T _{n + 3,} and (2/3) T _n > T _{n + 1} ... “Cycle decrease” (3/2) T _{n + 1} <T _{n +2} … “cycle increase” T _{n + 2} = T _{n + 3} … “no cycle increase / decrease”, and since “cycle decrease” is followed by a change tendency of “cycle increase”, “whiskers” occur. It is determined that there is a beard, and "beard" is complemented.

[0060] That is the two cycles of period T _n and the period T _{n + 1} as coupled to the drawing (b) to one, one period T
to complement the "beard" by processing as _{n +} T _n + _1.
In other words, in this case, processing is performed so as to cancel only one beard-shaped electric signal pulse, and this processing is expressed as complementing "whiskers" here.

FIG. 5 shows that the pressure sensor 10 detects the fluid vibration of the fluidic oscillator 7 and the period of the electric signal shaped into a square wave by the waveform shaping circuit 17 has a different change tendency from that of FIG. , Is a diagram for explaining the concept of the process when it is determined that "beard".

In this case, the period of the electric signal is as shown in FIG.
As in, following a period T _n, the period T _{n + 1,} the period T _{n + 2,} and continuous with the period _{T n + 3, (2/3)} T n> T n + 1 ... "cycle decrease" (2/3) T _{n + 1} <T _{n + 2} ≦ (3/2) T _{n + 2} … “No increase / decrease in cycle” (3/2) T _{n + 2} <T _{n + 3} … “cycle increase” Then, since the change tendency of "no cycle increase / decrease" and "cycle increase" appears successively in succession following "cycle decrease", it is also determined that "beard" has occurred, and "beard" Complement.

That is, two periods _{Tn + 1} and Tn _{+ 2} in FIG. 7A are processed as one period _{Tn + 1} + _{Tn + 2} as shown in FIG. That complements the "beard". In other words, in this case, processing is performed so as to cancel only one beard-shaped electric pulse, and this processing is expressed as complementing “whiskers” in this case as well.

Incidentally, as described above, the pressure sensor 10
The change tendency of the period of the electric signal is grasped, and it is determined whether "pulse missing" or "whisker" is obtained from the change tendency, and processing for complementing them is performed. The following processing is also performed as a whole processing procedure. .

(A) Initialization Processing At the time when the first cycle of the pressure sensor 10 is measured, comparison with the immediately preceding cycle cannot be made, and the change tendency from the immediately preceding cycle is unambiguously “no cycle increase / decrease”. And

Until the next cycle is measured, it is not determined whether or not the obtained cycle can be used as it is, so that it is stored as “pending data”. At the same time, data on the tendency to change the cycle is also stored.

(B) Sequential processing After the second cycle, the next (b) is performed based on the latest change tendency.
-1) and (b-2).

(B-1) If "pulse missing" or "whisker" is determined, processing corresponding to the contents is performed, and the latest cycle data is stored as "hold data".

The periodic data subjected to the "pulse missing" and "whisker" determination processing is transferred to the complemented data. At this time, the latest data of the change tendency of the cycle is “no change in the cycle”. (B-2) When it is not determined that “pulse missing” or “whiskers”, “suspended data” that is not affected by the next change tendency is transferred to complemented data, and other data are sequentially shifted. Then, it is stored as “pending data”. The data of the change tendency is similarly shifted and stored.

The change tendency after the "pulse missing" and "whisker" judgments is unambiguously determined by "(b-1)" as "unchanged period".
This is for the following reasons (c) and (d). (C) In order to avoid self-contradiction in processing, the complemented data is the flow rate measured by the fluidic oscillation element 7 (of the period of the electric signal of the pressure sensor 10 corresponding to).
It is used for the determination and the volume conversion, and the data once determined may be already executed for the flow rate measurement and the volume conversion based on the data.

If it is assumed that “period does not increase or decrease” and the increase / decrease comparison is performed again with the complemented period, it may be necessary to rewrite data already used for other processing. That is, there is a contradiction that the flow rate determination and the volume conversion performed in the past are erroneous.

(D) To minimize the processing delay In order to prevent the occurrence of the “self-contradiction” in the above item (c), the determined cycle defined as “post-complementation data” is directly processed by another processing. It is possible to cope with this by retaining the data as “pending data for the next process” without using it.

In this case, however, a new processing delay is added in addition to the delay until the data is determined as the complemented data. Next, a few examples of pulse complementation when gas is supplied to the gas meter according to this embodiment will be described.

FIG. 6 shows the waveform of the electric signal at the time of the steady flow of 170 [l / h]. FIG. 6 (a) shows the waveform before complementation, and FIG. 6 (b) shows the waveform after complementation. It can be seen that the "pulse missing" in FIG. 9A is complemented, and the pulse indicated by the symbol P in FIG.

FIG. 7 shows a steady flow 170 as in FIG.
FIG. 4A shows a waveform before complementation, in which the "whiskers" indicated by reference symbol P 'appear in the electric signal waveforms indicating the processing of complementing "whiskers" at [l / h].

In FIG. 11B, the "whiskers" P 'have disappeared, indicating that the "whiskers" have been complemented. 8A and 8B show waveforms of an electric signal when an unsteady flow having a varying flow rate flows. FIG. 8A shows a waveform before complementation, and FIG. 8B shows a waveform after complementation.

In the illustrated portion, "pulse missing" in FIG. 9A is complemented as shown in FIG. In the part shown in the figure, the "whiskers" in FIG. 7A are complemented as shown in FIG.

Next, switching control of the flow rate sensor by the first sensor switching determining section 23 will be described. First,
The average period calculating unit 22 is configured to compensate for the “pulse missing” or “whisker” by the pulse complementing unit 21 as described above.
The average value of a plurality of continuous periods, for example, N periods, is calculated for the electric signal of (1).

As shown in FIG. 9, before complementation in FIG.
"Pulse missing" of electric signal P_Three, P ₆Is the same as Fig. (B)
As shown in FIG.₁,
T_Two, T _ThreeAnd T_FourAverage period (T₁+ T_Two+ T_Three+ T
_Four) / 4 is calculated and calculated by the average period calculator 22.

The average value of a plurality of (N = 4) periods calculated in this way is compared with threshold values T _D and T _S stored in the sensor switching threshold value memory 31, and the average value of the period is calculated. When the pressure is on the downward trend and becomes smaller than the threshold value T _D , the pressure sensor is switched. That is, the switch 28 is switched to the position shown in FIG.

When the average value of the N (four) periods is on the rise and becomes larger than the threshold value T _S , the first sensor switching determination section 23 sets the switch 28 in the opposite state to that of FIG. Switching to the state, the measurement sensor is switched from the pressure sensor (fluidic oscillation element) to the flow sensor.

As described above, the first sensor switching determination section 23 switches the measurement sensor based on the average value of a plurality (N) of the electric signals of the pressure sensor 10. For this reason, there is no possibility that a frequent switching will occur unnecessarily.

As described above, the first sensor switching determination unit 23 determines which sensor should perform measurement based on the average period of the electric signal of the pressure sensor 10 calculated by the average period calculation unit 22. Therefore, if the gas flow stops during the measurement of N consecutive periods in order to calculate the average value of a plurality of (N) predetermined periods, the N average periods Is not calculated, the selection of the measurement sensor is not immediately executed.

Therefore, the second sensor switching determination section 32
Comes to the turn. In the second sensor switching determination unit 32, the Over value memory 33 sequentially stores the cycle of the electric signal of the pressure sensor 10 (strictly speaking, the square wave electric signal output from the waveform shaping circuit 17) one cycle at a time. Compare with the value Tover.

In the embodiment, Tover is set to be two to three times the threshold value T _S. And the pressure sensor 10
If the period T of the electric signal of the above is larger than the Over value, as shown in FIG. 10, after the electric signal P ₁ of the pressure sensor 10 and after the Over, the measurement sensor is switched from the pressure sensor 10 to the flow sensor 12. The second sensor switching determination unit 32 switches the switch 28. At this time, a flow sensor drive signal is simultaneously output from the flow sensor drive control circuit 24 to the flow sensor 12 (see FIG. 10).

In the above embodiment, the first sensor switching determination unit 23 determines that the threshold value when switching the measurement sensor from the pressure sensor to the flow sensor 12 is Q _S ,
In the cycle of the pressure sensor 10, it is T _S , and when the measurement sensor is switched from the flow sensor 12 to the pressure sensor 10, the threshold is Q _{D in} the flow rate, and T in the cycle of the pressure sensor 10.
_D is the hysteresis Q _D −
It has Q _S and a hysteresis T _S -T _D represented by a period.

However, in the present invention, the average period of a plurality (N) of the pulse-complemented electric signals of the pressure sensor 10 is calculated, and the switching of the measurement sensor is determined based on the average period. Compared with the prior art, the average period itself based on which the switching is determined is a stable numerical value with little fluctuation. Therefore, the hysteresis T _S −T _D is not always necessary, and the threshold value T _{D is set} to a threshold value. The hysteresis can be made substantially zero by determining the same value as the value T _S.

Next, a second embodiment of the present invention shown in FIG. 11 will be described. In the second embodiment, hardware and software for complementing "pulse missing" and "beard" are the first and the second in FIG.
This is the same as the embodiment. Further, based on the average value of a plurality of (N) cycles of the electric signal complemented by the pressure sensor 10, the first
This is the same as the first embodiment in FIG. 1 in that the sensor switching determination unit 23 controls the switch 28.

Therefore, in FIG. 11, of the second embodiment,
Only a part of the block diagram including a portion different from the first embodiment of FIG. 1 is shown. In the figure, after the electric signal of the pressure sensor 10 is amplified by the amplifier 11 and shaped into a square wave electric signal by the waveform shaping circuit 17, the total time of n consecutive cycles is measured by the n cycle time measuring unit 18A. Measured.

The value of n is preferably set to be equal to or smaller than the number N of the continuous cycles handled by the average period calculator 22 described in the first embodiment of FIG. 1, and is set to, for example, 2 in the second embodiment. It is.

Reference numeral 32A denotes a second sensor switching determination unit.
n pieces (n in the example, n pieces) measured by the n cycle time measuring unit 18A
= 2 the sum T ₁ + T ₂ of the cycle of), T _a value memory 33
Compared with the threshold T _a which is stored in the A, T ₁ + T ₂
> Switch from the position shown the selector switch 28 when the T _a, is to use the flow sensor 12 as a measuring sensor.

Threshold value T_nIs generally the threshold T
_SAnd the number N of the periods _S× N or less
However, in this embodiment, 3T_SStipulated. Therefore, FIG.
As shown in FIG._aStored in value memory 33A
3T as a threshold time_SPressure sensor between
Two non-pulse-complemented electrical pulses, ie P
₁And P_TwoPeriod T₁+ T_TwoIs not entered, the pulse P
₁From 3T_STime, the second sensor switching judgment
The circuit 32A transmits the measurement sensor from the pressure sensor 10 to the flow sensor.
Switch 28 to switch to sensor 12
Change control.

Then, the flow sensor drive control circuit 24 outputs a flow sensor drive signal (see FIG. 12).

[0094]

Since the fluidic gas meter of the present invention is configured as described above, "pulse missing" and "whiskers" due to fluctuations in the supply gas pressure are automatically complemented, and pulse complemented electricity is supplied. Since the first sensor switching determination circuit controls the switching of the measurement sensor based on the plurality of average periods of the signal, the switching of the sensor is not frequently performed unnecessarily, and the measurement error as the flow meter is not caused. Becomes smaller. Therefore, the measurement accuracy (instrument difference) of the gas meter is improved.

Further, even if the flow rate decreases during the measurement of the average period, the second sensor switching determination unit executes the switching control of the sensor promptly, so that there is no possibility that the system will malfunction.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing the entire embodiment of the present invention.

FIG. 3 shows “pulse missing” in the gas meter according to the embodiment of the present invention.
FIGS. 7A and 7B are diagrams illustrating the concept of a process in the case of complementing (a), where (a) is a diagram illustrating a waveform of an electric signal before complementation, and (b) is a diagram illustrating a waveform of an electric signal after complementation.

FIGS. 4A and 4B are diagrams for explaining the concept of processing in a case where “whiskers” are complemented by the gas meter according to the embodiment of the present invention. FIG. 4A shows a waveform of an electric signal before complementation, and FIG. FIG. 3 is a diagram illustrating a signal waveform.

FIGS. 5A and 5B are diagrams for explaining the concept of processing in a case where “whiskers” are complemented by the gas meter according to the embodiment of the present invention. FIG. 5A shows a waveform of an electric signal before complementation, and FIG. FIG. 3 is a diagram illustrating a signal waveform.

6A and 6B are waveforms of electric signals when a steady flow is applied to the gas meter according to the embodiment of the present invention. FIG. 6A shows a waveform before “pulse missing” complementation, and FIG. 6B shows a waveform after “pulse missing” complementation. It is a diagram showing a waveform.

7A and 7B are waveforms of electric signals when a steady flow is applied to the gas meter according to the embodiment of the present invention. FIG. 7A shows a waveform before “beard” complementation, and FIG. 7B shows a waveform after “beard” complementation. FIG.

FIGS. 8A and 8B are diagrams showing electric signal waveforms when an unsteady flow is applied to the gas meter according to the embodiment of the present invention. FIG. 8A is a diagram showing a signal waveform before complementation, and FIG. 8B is a diagram showing a signal waveform after complementation. It is.

9A and 9B are graphs showing electric signal waveforms of the gas meter according to the embodiment of the present invention, in which FIG. 9A shows a signal waveform before complementation and FIG. 9B shows a signal waveform after complementation. This figure is also a diagram for explaining the measurement of the average period of the electric signal after the complementation.

FIG. 10 is a diagram showing electric signal waveforms for explaining the operation of the second sensor switching determination unit of the gas meter according to the first embodiment of the present invention.

FIG. 11 is a diagram showing a main part of a block diagram of a second embodiment of the present invention.

FIG. 12 is a diagram showing electric signal waveforms for explaining an operation of a second sensor switching determination unit of the gas meter according to the second embodiment of the present invention.

FIG. 13 is a diagram illustrating a temporal change of a flow rate and a timing of an electronic circuit for explaining an operation of the embodiment of the present invention.

14A shows a waveform of an electric signal obtained by detecting a fluid vibration of a fluid oscillation element by a pressure sensor in a conventional technique, and FIG. 14B shows a flow sensor drive signal.

15A and 15B are diagrams illustrating “pulse omission” in a fluidic gas meter, where FIG. 15A shows an electric signal waveform of a pressure sensor, FIG. 15B shows an output electric signal waveform of a waveform shaping circuit, and FIG. 4 shows a flow sensor drive signal waveform.

FIG. 16 is a diagram of an electric signal waveform showing a temporal change of a flow rate and an electronic circuit timing for explaining an operation of a conventional gas meter, and is a diagram in a case where a supply gas pressure largely fluctuates.

FIG. 17 is a diagram for explaining the operation of the conventional gas meter, and is a diagram in the case where there is no large change in the supply gas pressure;
FIG. 17 is a view corresponding to FIG. 16.

[Explanation of symbols]

2 Nozzle 7 Fluidic oscillation element 10 Pressure sensor 12 Flow sensor 21 Pulse complementer 23 First sensor switching determining unit 32 Second sensor switching determining unit n, N Number of cycles T cycle T _S Threshold of cycle T _a Threshold of the total of n periods (constant value) Over Threshold of the period (constant value)

──────────────────────────────────────────────────続 き Continuing from the front page (73) Patent holder 000116633 Aichi Watch Electric Co., Ltd. 1-2-70, Millennial, Atsuta-ku, Nagoya-shi, Aichi (72) Inventor Ikko Itsui 9-10 Misonodai, Fujisawa-shi, Kanagawa (72) Inventor Katsuhito Sakai 2-2-7-123 Takasago, Katsushika-ku, Tokyo (72) Inventor Shinichi Sato 543-15, Kitanocho, Hachioji-shi, Tokyo (72) Inventor Shigenori Okamura Chuo-ku, Osaka-shi, Osaka 4-1-2 Hirano-cho Osaka Gas Co., Ltd. (72) Inventor Takato Sato 507-1 Shinhocho-cho, Tokai-shi, Aichi Prefecture Toho Gas Co., Ltd. (72) Inventor Masahito Naganuma Atsuta, Nagoya-shi, Aichi Prefecture Aichi Clock & Electronics Co., Ltd., 2-70, Sennichi-ku, Aku (72) Inventor Itsuro Hori 2-70, Millennial, Atsuta-ku, Nagoya-shi, Aichi Pref. Field (Int.Cl. ^7, DB name) G01F 1/00 - 9/02

Claims (4)

(57) [Claims] The fluid oscillation of a fluidic oscillation element is converted into an electric signal by a pressure sensor, a flow rate in a medium to large flow rate range is measured based on the electric signal, and the fluidic oscillation element is measured. (7) In a gas meter for measuring a flow rate in a small flow rate region based on an electric signal of a flow sensor (12) disposed in a nozzle (2) of (7), a period of the electric signal of the pressure sensor (10) is predetermined. Based on the threshold coefficient, successively compare and grasp the changing tendency,
A pulse complementer (21) for complementing "pulse missing" and "whiskers" in the electric signal of the pressure sensor (10) according to the change tendency, and a cycle (N) of a plurality of consecutive pulse-complemented electric signals. A first sensor switching determination unit (23) that calculates an average value and controls switching between the pressure sensor (10) and the flow sensor (12) based on the calculated average period; and the pressure sensor before pulse complementation. When the period (T) of the electric signal of (10) is equal to or greater than a predetermined value (Tover), a second sensor switching determination for preferentially controlling switching of the flow measurement sensor from the pressure sensor (10) to the flow sensor (12). A fluid gas meter, comprising: 2. A method according to claim 1, wherein the second sensor switching determination unit determines a constant value (Tover) of the period of the electric signal when the flow rate measurement sensor is switched from the pressure sensor to the flow sensor. Sensor switching determination unit (2)
3) the average period threshold value (T _s ) 2 when switching from the pressure sensor (10) to the flow sensor (12);
2. The fluidic gas meter according to claim 1, wherein the value is set between double and triple. 3. The fluid oscillation of a fluidic oscillation element (7) is converted into an electric signal by a pressure sensor (10), and a flow rate in a medium to large flow rate range is measured based on the electric signal. (7) In a gas meter for measuring a flow rate in a small flow rate region based on an electric signal of a flow sensor (12) disposed in a nozzle (2) of (7), a period of the electric signal of the pressure sensor (10) is predetermined. Based on the threshold coefficient, successively compare and grasp the changing tendency,
A pulse complementer (21) for complementing "pulse missing" and "whiskers" in the electric signal of the pressure sensor (10) according to the change tendency, and a cycle (N) of a plurality of consecutive pulse-complemented electric signals. A first sensor switching determination unit (23) that calculates an average value and controls switching between the pressure sensor (10) and the flow sensor (12) based on the calculated average period; and the pressure sensor before pulse complementation. The sum of the cycles of a plurality (n) of consecutive electric signals in (10) is a constant value (T _a )
A fluidic gas meter, comprising: a second sensor switching determination unit (32A) for controlling the flow measurement sensor from the pressure sensor (10) to the flow sensor (12) with priority in the above case. . 4. A pressure sensor (10) before pulse interpolation.
The number of periods (n) when calculating the total of the continuous periods of the electric signals of the above is set to be equal to or less than the number of periods (N) when calculating the average value of the continuous periods of the pulse-complemented electric signals, and The constant value (T _a ) comparing the sum of successive periods of the electrical signal of the pressure sensor (10) before pulse interpolation.
The threshold value (T _S ) of the average period when the first sensor switching determination unit (23) switches from the pressure sensor (10) to the flow sensor (12), and the continuous period of the pulse-complemented electric signal. 4. The fluidic gas meter according to claim 3, wherein the value is set to be equal to or less than the product (T _S × N) of the number of cycles (N) when calculating the average value of the fluid gas.