CN203069223U - Synchronous phase code time difference detection device for ultrasonic flowmeter - Google Patents

Abstract

The utility model discloses a synchronous phase code time difference detection device for an ultrasonic flowmeter. A pair of ultrasonic transducers is adopted as a transmitting and receiving signal probe set and is respectively installed on two sides of a pipeline to be separated by a distance. One measurement period of the synchronous time difference detection method comprises two processes: controlling the two ultrasonic transducers to be simultaneously used as a transmitting end to transmit 13 bit Barker code signals with different frequencies; and controlling the two ultrasonic transducers to stop transmitting the signals and wait for receiving the signals, and utilizing a related processing method to precisely measure and record the time when the first ultrasonic transducer transmits the signals to the second ultrasonic transducer and the time when the second ultrasonic transducer transmits the signals to the first ultrasonic transducer. According to the data, the device combines geometrical information to work out the flow velocity and the quantity of flow.

Description

Device for detecting difference when synchronous for the phase encoding of ultrasonic flow meter

Technical field

The utility model relates to the ultrasonic flow meter technology, device for detecting difference when particularly a kind of phase encoding for ultrasonic flow meter is synchronous.

Background technology

With respect to mechanical flow meter and electromagnetic type flow meter, ultrasonic flow meter has plurality of advantages: measuring accuracy height,, non-contact measurement strong to the adaptability of caliber, easy to use and be easy to digital management etc.Development along with piezoelectric ceramic technology, electronic technology and high-speed digital signal treatment technology, the performance of ultrasonic flow meter has had large increase, manufacturing cost also descends significantly simultaneously, so ultrasonic flow meter has obtained widespread use in industrial circle and daily life.

In the design of ultrasonic flow meter, adopt time difference method to carry out input at present mostly, below the detection principle of transit time ultrasonic flow meters is simply introduced.The transit time ultrasonic flow meters principle of work as shown in Figure 1, it is to utilize a pair of ultrasonic transducer transmitting-receiving ultrasound wave, measure flow rate of fluid by measuring ultrasound wave propagation time difference of following current and adverse current in fluid, come a kind of indirect measurement method of calculated flow rate again by flow velocity.

Two ultrasonic transducers are arranged in the accompanying drawing 1: transducer A and transducer B, two transducers are installed in the both sides of fluid line respectively and at a distance of certain distance, the interior diameter of pipeline is D, and the path that ultrasound wave is propagated is L, and the time that the ultrasound wave following current is propagated is t ₁, the time that adverse current is propagated is t ₂, the flow direction angle of hyperacoustic direction of propagation and fluid is θ.Because fluid flows, the used used time weak point of time ratio adverse current of distance of L length is propagated in the ultrasound wave following current, and the fluid-velocity survey principle can be represented with following formula:

$\left\{\begin{array}{c}{t}_1=\frac{L}{c+V\cos \mathrm{\θ}}\\ t_2=\frac{L}{c-V\cos \mathrm{\θ}}\end{array}\right.---\left(1\right)$

Wherein: c is the velocity of propagation of ultrasound wave in fluid media (medium), and V is the flowing velocity of target fluid.

Two formulas in the formula (1) are subtracted each other the mistiming Δ t that can obtain following current propagation and adverse current propagation:

$\mathrm{\Δt}=t_2-t_1=\frac{2\mathrm{VL}\cos \mathrm{\θ}}{c^2-V^2{\cos }^2\mathrm{\θ}}---\left(2\right)$

Because it is individual indivisible that rate of flow of fluid is compared with the velocity of propagation of ultrasound wave in medium, so formula (2) can be reduced to:

$\mathrm{\Δt}\≈\frac{2\mathrm{VL}\cos \mathrm{\θ}}{c^2}---\left(3\right)$

Thereby draw flow rate of fluid be:

$V=\frac{c^2\mathrm{\Δt}}{2L\cos \mathrm{\θ}}---\left(4\right)$

After recording flow velocity, by calculating the sectional area of pipeline, can draw that flow is in the pipe:

$Q=V*\mathrm{\π}\frac{D^2}{4}---\left(5\right)$

Wherein: Q is flow, and V is flow velocity, and D is the interior diameter of pipeline.

Existing transit time ultrasonic flow meters is carrying out the time difference when detecting, two kinds of methods below adopting usually:

Method one: adopt a pair of ultrasonic transducer A and transducer B(as shown in Figure 1), testing process is as follows:

1) ultrasonic transducer A is as transmitting terminal, and transducer B is as receiving end, and control transducer A transmits, and detects the signal that transducer B receives then, draws the ultrasound wave time t that following current is propagated in fluid ₁

2) ultrasonic transducer B is as transmitting terminal, and transducer A is as receiving end, and control transducer B transmits, and detects the signal that transducer A receives then, draws the ultrasound wave time t that adverse current is propagated in fluid ₂

3) calculate the mistiming Δ t=t that ultrasound wave following current and adverse current are propagated ₂-t ₁

Method two: adopt two couples of ultrasonic transducer A and transducer B, transducer C and transducer D(are as shown in Figure 2), testing process is as follows:

1) ultrasonic transducer A is as transmitting terminal, and transducer B is as receiving end, and control transducer A transmits, and detects the signal that transducer B receives then, draws the ultrasound wave time t that following current is propagated in fluid ₁Ultrasonic transducer C is as transmitting terminal simultaneously, and transducer D is as receiving end, and control transducer C transmits, and detects the signal that transducer D receives then, draws the ultrasound wave time t that adverse current is propagated in fluid ₂

2) calculate the mistiming Δ t=t that adverse current travel-time and following current are propagated ₂-t ₁

Consider the applicable cases in the reality, the deficiency that difference detection method exists during respectively from existing two kinds of measuring accuracy, power consumption and the tripartite surface analysis of manufacturing cost:

Method one measures the propagation that a time difference value needs ultrasound wave once to come and go in target fluid, if the inhomogeneous variation simultaneously of the flow velocity of target fluid is more frequent, method is not high once the time difference value real-time that measures so, the flow velocity real-time that calculates thus is not high yet, and the flow accuracy that calculates at last is not high yet.

Method two uses two pairs of ultrasonic transducers to measure, though can shorten the time that measures a time difference value like this, but increased the complexity of control and testing circuit, also can strengthen simultaneously the power consumption of whole flowmeter, power consumption also is an important indicator must considering in the design in actual applications.

In actual applications, manufacturing cost also is to weigh the major criterion of a design quality, and method two has used two pairs of transducers, and control and testing circuit complexity are very high simultaneously, when increasing power consumption, have also increased manufacturing cost.

Summary of the invention

Device for detecting difference when the purpose of this utility model is to provide a kind of phase encoding for ultrasonic flow meter synchronous, the subject matter that solve are how to make transit time ultrasonic flow meters satisfy measuring accuracy height, problem low in energy consumption simultaneously.

The technical scheme that its technical matters that solves the utility model adopts is:

The utility model proposes a kind of phase encoding for ultrasonic flow meter device for detecting difference when synchronous, comprising: first ultrasonic transducer, second ultrasonic transducer, first correlator, second correlator, first display, second display, sign indicating number generator; First ultrasonic transducer and second ultrasonic transducer, also stagger mutually by the both sides that are bolted to the fluid line tube wall, the interior diameter of pipeline is D, the path that ultrasound wave is propagated is L(L＞D), the direction that ultrasound wave is propagated and the flow direction angle of fluid are θ (0 °＜θ＜90 °), first ultrasonic transducer is connected with first correlator, second ultrasonic transducer is connected with second correlator, first correlator is connected with first display, second correlator is connected with second display, the sign indicating number generator respectively with first ultrasonic transducer, second ultrasonic transducer, first correlator, second correlator connects.

First ultrasonic transducer and second ultrasonic transducer are identical ultrasonic transducer; First correlator and second correlator are two identical correlators; Display and display are two identical displays.

Correlator is composed in parallel by some identical branch roads, and every multiplier of route and a low-pass filter are composed in series.

Ultrasonic transducer adopts the 200K-75KHz underwater acoustic transducer of Hangzhou An Buleila robotization Science and Technology Ltd., and model is XIHUW-75/200-E.

The beneficial effect that the utlity model has is:

Different with the common time difference detection method that adopts, device for detecting difference and method can reduce the influence that ultrasound wave changes in the medium velocity of propagation when phase encoding that is used for ultrasonic flow meter that the utility model provides was synchronous, adopt the relevant treatment method to measure ultrasound wave following current propagation and adverse current travel-time simultaneously, can significantly improve the measuring accuracy of ultrasonic flow meter.Difference detection method is compared during with tradition, and the utility model also satisfies the demand of low-power consumption, for the design of transit time ultrasonic flow meters provides a kind of more suitable detection method.What this method was launched is the ultrasonic signal of different frequency, can effectively avoid ultrasound wave to produce the influence that standing wave causes measurement result in propagating mutually.

Description of drawings

Fig. 1 is the measuring principle synoptic diagram of transit time ultrasonic flow meters.

Fig. 2 adopts two pairs of ultrasonic transducers to realize the measuring principle synoptic diagram of transit time ultrasonic flow meters.

Fig. 3 is the measuring principle synoptic diagram that phase encoding is modulated synchronous time difference detection method ultrasonic flow meter.

Fig. 4 is the relevant treatment principle schematic.

Fig. 5 is the autocorrelation function of 13 Barker codes.

Fig. 6 be display output apart from autocorrelation function.

Embodiment

In conjunction with Fig. 3, Fig. 4 and Fig. 5, the utility model proposes a kind of phase encoding for ultrasonic flow meter device for detecting difference when synchronous, comprising: first ultrasonic transducer 1, second ultrasonic transducer 2, first correlator 3, second correlator 4, first display 5, second display 6, sign indicating number generator 7; First ultrasonic transducer 1 and second ultrasonic transducer 2, also stagger mutually by the both sides that are bolted to the fluid line tube wall, the interior diameter of pipeline is D, the path that ultrasound wave is propagated is L(L＞D), the direction that ultrasound wave is propagated and the flow direction angle of fluid are θ (0 °＜θ＜90 °), first ultrasonic transducer 1 is connected with first correlator 3, second ultrasonic transducer 2 is connected with second correlator 4, first correlator 3 is connected with first display 5, second correlator 4 is connected with second display 6, the sign indicating number generator 7 respectively with first ultrasonic transducer 1, second ultrasonic transducer 2, first correlator 3, second correlator 4 connects.

First ultrasonic transducer 1 and second ultrasonic transducer 2 are identical ultrasonic transducer; First correlator 3 and second correlator 4 are two identical correlators; Display 5 and display 6 are two identical displays.

Correlator is composed in parallel by some identical branch roads, and every multiplier of route and a low-pass filter are composed in series.

Ultrasonic transducer adopts the 200K-75KHz underwater acoustic transducer of Hangzhou An Buleila robotization Science and Technology Ltd., and model is XIHUW-75/200-E.

Difference detection method when a kind of phase encoding for ultrasonic flow meter is synchronous, step is as follows:

The first step: the sign indicating number generator produce 13 Barker code signals and with 13 different time delayses that the Barker code signal is corresponding, will with the corresponding different time delays of 13 Barker code signals as different reference signals, and corresponding different time; The sign indicating number generator will produce 13 Barker code signals and pass to first ultrasonic transducer 1 and second ultrasonic transducer 2 respectively, and reference signal is passed to first correlator 3, second correlator 4 respectively.

Second step: first ultrasonic transducer 1 and second ultrasonic transducer 2 produce 13 Barker code signals as transmitting terminal transmitter code generator simultaneously.

The 3rd step: first ultrasonic transducer 1 receives the signal that second ultrasonic transducer 2 is launched as receiving end, and second ultrasonic transducer 2 receives the signal of first ultrasonic transducer, 1 emission as receiving end.

The 4th step: in correlator, identical with the time delay of sign indicating number generator when 13 travel-times of Barker code signal in fluid that receive, the output signal maximum of this branch road then, the main peak of respective distances autocorrelation function, this moment, this branch road was the travel-time of ultrasound wave in fluid corresponding time delay, and the following current travel-time is designated as t ₁Be designated as t with the adverse current travel-time ₂

The 5th step: calculate the mistiming Δ t=t that ultrasound wave following current and adverse current are propagated ₂-t ₁

The 6th step: utilize the mistiming Δ t that calculates in the 5th step, according to formula (4), can calculate the flow velocity V of detected fluid.

The 7th step: utilize the flow velocity V of the detected fluid that draws in the 6th step, according to formula (5), can calculate fluid flow Q.

Embodiment: setting fluid line interior diameter to be measured is 3m, the path that ultrasound wave is propagated is 5m, the flow direction angle of hyperacoustic direction of propagation and fluid is 36.87 °, the velocity of propagation of ultrasound wave in fluid is 1600m/s, 13 Barker code bursts that the sign indicating number generator generates are [11111-1-111-11-11], the different delayed time that produces 13 Barker code reference signals simultaneously be 2500 μ s, 2501 μ s, 2502 μ s ..., 3500 μ s.

The first step: first ultrasonic transducer 1 and second ultrasonic transducer 2 are installed in the both sides of pipeline tube wall respectively and stagger mutually; Sign indicating number generator 7 produce 13 Barker code signals and with 13 different time delayses that the Barker code signal is corresponding, will with the corresponding different time delays of 13 Barker code signals as different reference signals, and corresponding different time; Sign indicating number generator 7 will produce 13 Barker code signals and pass to first ultrasonic transducer 1 and second ultrasonic transducer 2 respectively, and reference signal is passed to first correlator 3, second correlator 4 respectively;

Second step: first ultrasonic transducer 1 and second ultrasonic transducer 2 produce 13 Barker code signals as transmitting terminal transmitter code generator simultaneously;

The 3rd step: first ultrasonic transducer 1 receives the signal that second ultrasonic transducer 2 is launched as receiving end, and second ultrasonic transducer 2 receives the signal of first ultrasonic transducer, 1 emission as receiving end;

The 4th step: in first correlator 3, time delays is the reference signal output ultimate range autocorrelation function peak value of 3156 μ s, therefore the travel-time that arrives first ultrasonic transducer 1 that transmits that records second ultrasonic transducer 2 is 3156 μ s, i.e. adverse current travel-time t ₂Be 3156 μ s; In second correlator 4, time delays is the reference signal output ultimate range autocorrelation function peak value of 3094 μ s, therefore the travel-time that arrives second ultrasonic transducer 2 that transmits that records first ultrasonic transducer 1 is 3094 μ s, i.e. following current travel-time t ₁Be 3094ts.Wherein display output apart from autocorrelation function as shown in Figure 6.

The 5th step: the mistiming Δ t that calculates the propagation of ultrasound wave following current and adverse current is 62 μ s.

The 6th step: according to formula (4), the flow velocity V that can calculate detected fluid is 19.84m/s.

The 7th step: according to formula (5), can calculate fluid flow Q is 140.2406m ³/ s.

Claims (3)

1. device for detecting difference when the phase encoding for ultrasonic flow meter is synchronous, comprise: first ultrasonic transducer (1), second ultrasonic transducer (2), first correlator (3), second correlator (4), first display (5), second display (6), sign indicating number generator (7), it is characterized in that: first ultrasonic transducer (1) and second ultrasonic transducer (2), also stagger mutually by the both sides that are bolted to the fluid line tube wall, the interior diameter of pipeline is D, the path that ultrasound wave is propagated is L, and L＞D, the direction that ultrasound wave is propagated and the flow direction angle of fluid are θ, 0 °＜θ＜90 ° wherein, first ultrasonic transducer (1) is connected with first correlator (3), second ultrasonic transducer (2) is connected with second correlator (4), first correlator (3) is connected with first display (5), second correlator (4) is connected with second display (6), the sign indicating number generator (7) respectively with first ultrasonic transducer (1), second ultrasonic transducer (2), first correlator (3), second correlator (4) connects.

2. device for detecting difference when a kind of phase encoding for ultrasonic flow meter according to claim 1 is synchronous is characterized in that: first ultrasonic transducer (1) and second ultrasonic transducer (2) are identical ultrasonic transducer; First correlator (3) and second correlator (4) are two identical correlators; Display (5) and display (6) are two identical displays.

3. device for detecting difference when a kind of phase encoding for ultrasonic flow meter according to claim 1 is synchronous is characterized in that: correlator is composed in parallel by some identical branch roads, and every multiplier of route and a low-pass filter are composed in series.

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