CN104236646B - Ultrasonic flowmeter and ultrasonic flow measuring method - Google Patents
Ultrasonic flowmeter and ultrasonic flow measuring method Download PDFInfo
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- CN104236646B CN104236646B CN201310308284.6A CN201310308284A CN104236646B CN 104236646 B CN104236646 B CN 104236646B CN 201310308284 A CN201310308284 A CN 201310308284A CN 104236646 B CN104236646 B CN 104236646B
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Abstract
The invention discloses an ultrasonic flowmeter and an ultrasonic flow measuring method. The ultrasonic flowmeter includes a zero point detection circuit and an arithmetic processing circuit. The zero detection circuit comprises a digital-analog converter, a pre-trigger comparator, a zero cross comparator and an AND gate. The digital-to-analog converter generates a multi-stage trigger signal. The pre-trigger comparator compares the ultrasonic echo with the multi-stage trigger signal to output a first comparison signal. The zero-crossing comparator compares the ultrasonic echo with a reference level to output a second comparison signal. The AND gate performs an intersection operation on the first comparison signal and the second comparison signal to output a zero-crossing digital signal. The arithmetic processing circuit calculates the ultrasonic flow rate from the zero-crossing digital signal.
Description
Technical field
The present invention relates to a kind of ultrasonic flowmeter and ultrasonic flow measuring method.
Background technology
Ultrasonic flowmeter group is mountable to pipeline surface, it is not necessary to which the flow in pipeline can be measured by cutting off pipeline, or
It is installed on direct measurement flow on pipeline.Ultrasonic flowmeter is mainly used to the uniform fluid flow of measurement cleaning, in oil, changes
Work, metallurgy, electric power, Running-water Company and industrial water and river, recycle-water field, are used widely, in addition ultrasonic wave
Flowmeter can measure the not high homogeneous (uniform) fluid of impurity content, such as flow of sewage medium, if bubble or body during pipe is interior
The larger solids of product can not then be measured.
Traditional transit-time ultrasonic flow meter needs that one group of peak detection circuit is used alone to judge ultrasonic echo
Intensity, then it is supplied to gain control circuit to make waveform amplification feedback control the intensity of ultrasonic echo.Followed by ultrasonic wave
The first wave of echo, detects circuit to judge the ultrasonic wave flight time with zero crossings.However, traditional transit-time ultrasonic flow amount
Meter is because only detect first wave zero crossings, easily because of interference effect accuracies in measurement such as bubble, the impurity in fluid.
The content of the invention
The present invention relates to a kind of ultrasonic flowmeter and ultrasonic flow measuring method.
According to the present invention it is proposed that a kind of ultrasonic flowmeter.Ultrasonic flowmeter is included at zero-detection circuit and computing
Manage circuit.Zero-detection circuit include digital analog converter, pre-trigger comparator, zero crossings comparator and with door (AND
gate).Digital analog converter produces a multistage trigger signal.Pre-trigger comparator compares ultrasonic echo and touched with the multistage
Signal to export the first comparison signal.Zero crossings comparator compares ultrasonic echo and compared with datum with exporting second
Signal.Carry out an intersection operation to export a zero crossing (Zero-cross) with the comparison signal of goalkeeper first and the second comparison signal
Data signal.Arithmetic processing circuit calculates ultrasonic flow according to zero crossing data signal.
According to the present invention it is proposed that a kind of ultrasonic flow measuring method.Ultrasonic flow measuring method includes：Produce multistage
Section trigger signal；Ultrasonic echo is compared with the multistage trigger signal by pre-trigger comparator and is compared letter to export first
Number；Compare ultrasonic echo with datum to export the second comparison signal by zero crossings comparator；Compare letter by first
Number an intersection operation is carried out to export a zero crossing (Zero-cross) data signal with the second comparison signal；And handed over according to zero
Pitch data signal and calculate ultrasonic flow.
Brief description of the drawings
Fig. 1 is a kind of embodiment circuit box schematic diagram of ultrasonic flowmeter；
Fig. 2 is the schematic diagram of zero-detection circuit；
Fig. 3 is ultrasonic echo, the first comparison signal, the second comparison signal, the timing diagram of zero crossing data signal；
Fig. 4 is the schematic diagram of multistage trigger signal and ultrasonic echo；
Fig. 5 is the numeric distribution figure of the zero crossing time array of non-filtered calculation；
Fig. 6 is the numeric distribution figure of the filtered data of filtered calculation.
【Description of reference numerals】
1：Ultrasonic flowmeter
11a、11b：Ultrasonic probe
12a、12b：Driver
13a、13b：Switch
14：Bandpass filter
15：Variable gain amplifier
16：Zero-detection circuit
17：Arithmetic processing circuit
18：Time measuring circuit
19：Wireless communication module
161：Digital analog converter
162：Pre-trigger comparator
163：Zero crossings comparator
164：With door
165：NAND gate
PTL (1)~PTL (M)：Pre-trigger level
MS：Multistage trigger signal
Rx：Ultrasonic echo
Rst：Reset signal
C1：First comparison signal
C2：Second comparison signal
Ny：Noise
L：Latch-up signal
ZCD：Zero crossing data signal
ZC(1)：Pre-trigger word pulse
ZC(2)：Zero crossing digit pulse
SP：Initial pulse
Embodiment
For the object, technical solutions and advantages of the present invention are more clearly understood, below in conjunction with specific embodiment, and reference
Accompanying drawing, the present invention is described in further detail.
Fig. 1 is refer to, Fig. 1 is a kind of embodiment circuit box schematic diagram of ultrasonic flowmeter.Ultrasonic flowmeter 1 is wrapped
Include ultrasonic probe 11a, ultrasonic probe 11b, driver 12a, driver 12b, switch 13a, switch 13b, bandpass filter
14th, variable gain amplifier 15, zero-detection circuit 16, arithmetic processing circuit 17, time measuring circuit 18 and radio communication mold
Block 19.Driver 12a is to drive ultrasonic probe 11a, and driver 12b is to drive ultrasonic probe 11b.Ultrasonic wave is visited
Head 11a and ultrasonic probe 11b alternately launches ultrasonic wave with receiving ultrasonic echo.
When switching 13a conductings, switch 13b accordingly ends.On the contrary, when switching 13a cut-offs, switch 13b correspondences
Ground is turned on.Bandpass filter 14 is to by the noise filtering beyond ultrasonic frequency range.Variable gain amplifier 15 is according to anti-
Feedback signal is exported to zero-detection circuit 16 after adjusting received ultrasonic echo.When time measuring circuit 18 calculates an overtime
Between.Wireless communication module 19 is used to transmitting/receiving wireless signal.Arithmetic processing circuit 17 is, for example, microcontroller, and wireless communication module
19 be, for example, ZigBee module.
Referring to Fig. 1, Fig. 2 and Fig. 3, Fig. 2 is the schematic diagram of zero-detection circuit, and Fig. 3 is ultrasonic echo, first
Comparison signal, the second comparison signal, the timing diagram of zero crossing data signal.Zero-detection circuit 16 includes digital analog converter
161st, pre-trigger comparator 162, zero crossings comparator 163 and door (AND gate) 164 and NAND gate (NAND gate)
165.The control digital analog converter 161 of arithmetic processing circuit 17 produces multistage trigger signal MS.Pre-trigger comparator 162 compares
After ultrasonic echo Rx and multistage trigger signal MS, the first comparison signal C1 is exported.Zero crossings comparator 163 is relatively super
Sound echo Rx and a datum are to export the second comparison signal C2.Datum is, for example, earth level.With door 164 by
One comparison signal C1 and the second comparison signal C2 carries out an intersection operation to export zero crossing data signal ZCD.Zero crossing numeral
Signal ZCD includes adjacent pre-trigger word pulse ZC (1) and zero crossing digit pulse ZC (2), pre-trigger word pulse ZC (1)
Produce at first, zero crossing digit pulse ZC (2) is closest to pre-trigger word pulse ZC (1).NAND gate 165 is by the first comparison signal
The reset signal Rst that C1 and arithmetic processing circuit 17 are exported carries out a reciprocal cross set operation to produce a latch-up signal L, latch-up signal
The latch mode of L control pre-trigger comparator 162.Arithmetic processing circuit 17 calculates ultrasonic wave according to zero crossing data signal ZCD
Flow.By the zero crossing data signal ZCD exported with door 164 is by the first comparison signal C1 and the second comparison signal C2 friendships
Collection and obtain, therefore be avoided that and influenceed and wrong judged by noise Ny.
Furthermore, it is understood that the selection zero crossing digit pulse ZC of arithmetic processing circuit 17 (2) is used as calculating flight time TOF's
Terminate pulse.Arithmetic processing circuit 17 calculates flight time TOF according to zero crossing digit pulse ZC (2), and the flight time, TOF was
Initial pulse SP and zero crossing digit pulse ZC (2) time difference.Arithmetic processing circuit 17 replaces further according to two groups of ultrasonic probes
Flight time TOF mathematic interpolation ultrasonic flow.
Referring to Fig. 1, Fig. 3 and Fig. 4, Fig. 4 is the schematic diagram of multistage trigger signal and ultrasonic echo.Multistage
Trigger signal MS includes pre-trigger level PTL (1)~PTL (M), and M is greater than 1 positive integer.Pre-trigger level PTL (1)~
PTL (M) is sequentially produced, and pre-trigger level PTL (1)~PTL (M) is sequentially incremented by.For example, pre-trigger level PTL (1)~
PTL (M) is sequentially incremented by 15mV.When pre-trigger level PTL (M) is equal to 3000mV, then M etc. 200.
Arithmetic processing circuit 17 corresponds respectively to pre-trigger level PTL (1) according to zero crossing data signal ZCD generations are several
~PTL (M) zero crossing time array.All zero crossing time arrays are first carried out a filtering operation by arithmetic processing circuit 17,
To produce a filtered data, arithmetic processing circuit 17 calculates ultrasonic flow further according to filtered data.Foregoing filtering operation
A for example, median average filter computing.Median average filter computing is first to be stored in array after sampling N pen datas, then by battle array
Row do size sequence.Median is taken afterwards, then subtracts each other the side data of median two and median.And then, judge after subtracting each other
As a result whether it is less than admissible error value.Then stop when the result after subtracting each other is less than admissible error value.Then the end of array two is noted down
Address A and B, then array x (A) to x (B) value is done into average computation, resulting value is filtered data.
In addition, arithmetic processing circuit 17 can also calculate ultrasonic echo Rx's according to pre-trigger word pulse ZC (1)
Peak swing, and using peak swing as variable gain amplifier 15 feedback signal.Pre-trigger level PTL (1)~PTL (M)
Including adjacent pre-trigger level PTL (M-1) and pre-trigger level PTL (M), and pre-trigger level PTL (M) is more than pre-trigger electricity
Flat PTL (M-1).When multistage trigger signal MS is equal to pre-trigger level PTL (M-1), arithmetic processing circuit 17 is when overtime
It is interior to receive pre-trigger word pulse ZC (1).Relatively, when multistage trigger signal MS is equal to pre-trigger level PTL (M),
Arithmetic processing circuit 17 is in can not receive pre-trigger word pulse ZC (1) in the overtime time.Arithmetic processing circuit 17 selects pre- touch
Flat PTL (M-1) is generated electricity as peak swing.
It is the numeric distribution figure of the zero crossing time array of non-filtered calculation, Fig. 6 referring to Fig. 5 and Fig. 6, Fig. 5
For the numeric distribution figure of the filtered data of filtered calculation.For example, using three English inch PVCs, fluid for it is static from
Water and sampled data are 828.Standard deviation average out to 61ns before non-filtered calculation as seen from Figure 5.Relatively, by
Fig. 6 can be seen that the standard deviation average out to 0.24ns after filtered calculation, it will be apparent that the amplitude of reduction numerical value bounce.
Particular embodiments described above, has been carried out further in detail to the purpose of the present invention, technical scheme and beneficial effect
Describe in detail bright, it should be understood that the foregoing is only the present invention specific embodiment, be not intended to limit the invention, it is all
Within the spirit and principles in the present invention, any modifications, equivalent substitutions and improvements done etc. should be included in the protection of the present invention
Within the scope of.
Claims (18)
1. a kind of ultrasonic flowmeter, including：
One zero-detection circuit, including：
One digital analog converter, to produce a multistage trigger signal, the multistage trigger signal includes multiple pre-trigger
Level, those pre-trigger level are sequentially produced, and those pre-trigger level are sequentially incremented by fixed increment；
One pre-trigger comparator, is compared letter to compare a ultrasonic echo with the multistage trigger signal to export one first
Number；
One zero crossings comparator, to compare the ultrasonic echo and a datum to export one second comparison signal；And
One with door (AND gate), to by first comparison signal and second comparison signal, one intersection operation of progress to export
One zero crossing (Zero-cross) data signal；And
One arithmetic processing circuit, to calculate a ultrasonic flow, the arithmetic processing circuit root according to the zero crossing data signal
Multiple zero crossing time arrays are produced according to the zero crossing data signal, it is pre- tactile that those zero crossing time arrays correspond respectively to those
Generate electricity flat.
2. ultrasonic flowmeter as claimed in claim 1, it is characterised in that the zero-detection circuit also includes a NAND gate
(NAND gate), first comparison signal and a reset signal are carried out into a reciprocal cross set operation to produce a latch-up signal,
The latch-up signal controls the latch mode of the pre-trigger comparator.
3. ultrasonic flowmeter as claimed in claim 1, it is characterised in that it is pre- that the zero crossing data signal includes adjacent one
Digit pulse and a zero crossing digit pulse are triggered, the pre-trigger word pulse is produced at first, and the zero crossing digit pulse most connects
The nearly pre-trigger word pulse.
4. ultrasonic flowmeter as claimed in claim 3, it is characterised in that the arithmetic processing circuit is according to zero crossing numeral
Pulse calculates a flight time, and the arithmetic processing circuit calculates this according to the alternate flight time difference of two groups of ultrasonic probes and surpassed
Acoustic wave flow.
5. ultrasonic flowmeter as claimed in claim 3, it is characterised in that the arithmetic processing circuit is according to pre-trigger numeral
Pulse calculates a peak swing of the ultrasonic echo.
6. ultrasonic flowmeter as claimed in claim 5, it is characterised in that also include：
One variable gain amplifier, the arithmetic processing circuit using the peak swing as the variable gain amplifier feedback letter
Number.
7. ultrasonic flowmeter as claimed in claim 5, it is characterised in that also include：
One time measuring circuit, to calculate the overtime time, those pre-trigger level include adjacent one first pre-trigger electricity
Flat and one second pre-trigger level, and the second pre-trigger level is more than the first pre-trigger level, believes when the multistage triggers
When number being equal to the first pre-trigger level, the arithmetic processing circuit in receiving the pre-trigger word pulse in the overtime time, when
When the multistage trigger signal is equal to the second pre-trigger level, the arithmetic processing circuit in the overtime time in can not receive this
Pre-trigger word pulse, the arithmetic processing circuit selects the first pre-trigger level as the peak swing.
8. ultrasonic flowmeter as claimed in claim 1, it is characterised in that the arithmetic processing circuit is by those zero crossing times
Array carries out a filtering operation, to produce a filtered data, and the arithmetic processing circuit calculates this according to the filtered data and surpassed
Acoustic wave flow.
9. ultrasonic flowmeter as claimed in claim 8, it is characterised in that the filtering operation is transported for a median average filter
Calculate.
10. a kind of ultrasonic flow measuring method, including：
Produce a multistage trigger signal, the multistage trigger signal include multiple pre-trigger level, those pre-trigger level according to
Sequence is produced, and those pre-trigger level are sequentially incremented by fixed increment；
Compare a ultrasonic echo with the multistage trigger signal to export one first comparison signal by a pre-trigger comparator；
Compare the ultrasonic echo and a datum to export one second comparison signal by a zero crossings comparator；
First comparison signal and second comparison signal are carried out an intersection operation to export a zero crossing (Zero-cross)
Data signal；
One ultrasonic flow is calculated according to the zero crossing data signal；And
Multiple zero crossing time arrays are produced according to the zero crossing data signal, those zero crossing time arrays correspond respectively to this
A little pre-trigger level.
11. ultrasonic flow measuring method as claimed in claim 10, is characterised by, also include：
First comparison signal and a reset signal are subjected to a reciprocal cross set operation to produce a latch-up signal, the latch-up signal control
Make the latch mode of the pre-trigger comparator.
12. ultrasonic flow measuring method as claimed in claim 10, it is characterised in that the zero crossing data signal includes phase
An adjacent pre-trigger word pulse and a zero crossing digit pulse, the pre-trigger word pulse are produced at first, zero crossing numeral
Pulse is closest to the pre-trigger word pulse.
13. ultrasonic flow measuring method as claimed in claim 12, it is characterised in that the calculation procedure includes：
One flight time was calculated according to the zero crossing digit pulse；And
The ultrasonic flow is calculated according to the alternate flight time difference of two groups of ultrasonic probes.
14. ultrasonic flow measuring method as claimed in claim 12, it is characterised in that also include：
A peak swing of the ultrasonic echo is calculated according to the pre-trigger word pulse.
15. ultrasonic flow measuring method as claimed in claim 14, it is characterised in that also include：
Using the peak swing as a variable gain amplifier feedback signal.
16. ultrasonic flow measuring method as claimed in claim 14, it is characterised in that also include：
The overtime time is calculated, those pre-trigger level include one first adjacent pre-trigger level and one second pre-trigger electricity
It is flat, and the second pre-trigger level is more than the first pre-trigger level；
Wherein, when the multistage trigger signal is equal to the first pre-trigger level, in receiving the pre-trigger in the overtime time
Digit pulse；
Wherein, it is pre- in this can not be received in the overtime time when the multistage trigger signal is equal to the second pre-trigger level
Digit pulse is triggered, the first pre-trigger level is selected as the peak swing.
17. ultrasonic flow measuring method as claimed in claim 10, it is characterised in that the calculation procedure is by those zero crossings
Time array carries out a filtering operation, and to produce a filtered data, the ultrasonic flow is calculated further according to the filtered data.
18. ultrasonic flow measuring method as claimed in claim 17, it is characterised in that the filtering operation is flat for a median
Equal filtering operation.
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| TW102121715 | 2013-06-19 | ||
| TW102121715A TWI500908B (en) | 2013-06-19 | 2013-06-19 | Ultrasonic flow meter and ultrasonic flow measuring |
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| CN104236646B true CN104236646B (en) | 2017-07-14 |
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| JP6484131B2 (en) * | 2015-06-30 | 2019-03-13 | 株式会社堀場エステック | Flow measuring device |
| TWI576126B (en) * | 2016-02-03 | 2017-04-01 | 金宙科技有限公司 | A device of liquid flow measurement |
| CN107131918B (en) * | 2017-07-02 | 2023-09-12 | 中国计量大学 | Echo signal processing method and circuit of low-power-consumption ultrasonic flowmeter |
| CN107478282B (en) * | 2017-08-17 | 2020-09-01 | 西南科技大学 | Ultrasonic flow detection signal processing method and device and time difference method ultrasonic detection system |
| CN110221202B (en) * | 2019-07-17 | 2021-05-18 | 西安西电开关电气有限公司 | Current curve processing method and device for working current of circuit breaker |
| TWI692639B (en) * | 2019-10-03 | 2020-05-01 | 佳世達科技股份有限公司 | Ultrasonic probe |
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| CN201795819U (en) * | 2010-06-10 | 2011-04-13 | 宁波大学 | Static drift rejection model of time difference method ultrasonic flowmeter |
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| US4938054A (en) * | 1989-05-03 | 1990-07-03 | Gilbarco Inc. | Ultrasonic linear meter sensor for positive displacement meter |
| NZ243293A (en) * | 1991-06-25 | 1995-03-28 | Commw Scient Ind Res Org | Fluid flow meter: time of travel of acoustic wave packet through fluid |
| JP4020455B2 (en) * | 1997-05-28 | 2007-12-12 | 愛知時計電機株式会社 | Ultrasonic flow meter |
| JP2002365109A (en) * | 2001-06-11 | 2002-12-18 | Aichi Tokei Denki Co Ltd | Ultrasonic flowmeter |
| TWI259900B (en) * | 2001-10-02 | 2006-08-11 | Matsushita Electric Ind Co Ltd | Flow meter |
| JP3585476B2 (en) * | 2002-03-15 | 2004-11-04 | 松下電器産業株式会社 | Flow measurement device |
| JP4511257B2 (en) * | 2004-06-21 | 2010-07-28 | 愛知時計電機株式会社 | Ultrasonic flow meter |
| DE102006062552B4 (en) * | 2006-12-29 | 2009-12-24 | Bartels Mikrotechnik Gmbh | Method and device for flow measurement |
| JP4875780B2 (en) * | 2010-06-22 | 2012-02-15 | 株式会社泉技研 | Ultrasonic flow measuring device and ultrasonic flow measuring method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201795819U (en) * | 2010-06-10 | 2011-04-13 | 宁波大学 | Static drift rejection model of time difference method ultrasonic flowmeter |
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| TWI500908B (en) | 2015-09-21 |
| TW201500722A (en) | 2015-01-01 |
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