CN101097161A - Device for ultrasonic measuring liquid level and method thereof - Google Patents

Abstract

The invention discloses a device and method of measuring liquid using ultrasonic. The device includes: a signal generator; a data collecting device; a data process device; it is characterized in that it also includes an ultrasonic sending probe and at least two ultrasonic receiving probes which are fixed to a probe fixation device. The method includes following steps: 1)an ultrasonic sending probe sends ultrasonic to surface of liquid; 2)at least two ultrasonic receiving probes receive ultrasonic reflected from surface of liquid detected; 3)time of ultrasonic from sending to receiving is recorded; 4)radial distance and lognitudinal distance between said ultrasonic receiving probes and said ultrasonic sending probe are ensured; 5)altitude of liquid can be obtained by said time of ultrasonic and said radial distance and lognitudinal distance. The invention does not need to consider speed of sound, and precision of measuring liquid is increased.

Description

A kind of device and method of ultrasonic measuring liquid level

Technical field

The present invention relates to a kind of liquid level gauge, particularly relate to a kind of device and method of ultrasonic measuring liquid level, can measure the height of various liquid exactly.

Background technology

Ultrasonic technology is existing the irreplaceable superiority of other type instrument aspect the measuring liquid level height, convenient such as Installation and Debugging, Maintenance and Repair are simple, the precision height, and performance is good etc.Therefore, in the level gauging of industrial enterprise, obtained using widely.

The technology of existing ultrasonic measuring liquid level often needs to consider hyperacoustic velocity of sound, as at document 1: disclosed technology in " in the principle and the application of ultrasonic level gage; Zhang Xiaoyan; Heilungkiang papermaking; 2004 the 3rd phases ", as shown in Figure 1, this technology with a transmitting-receiving close the ultrasonic probe of putting be installed in tested liquid directly over, after this ultrasonic probe is subjected to electric excitation, by the liquid emission ultrasound wave of air to its below, ultrasound wave is reflected by liquid surface, and echo is closed the probe of putting by this transmitting-receiving and receives and measure, and ultrasonic signal is converted to electric signal.Ultrasound wave is that liquid level is to the ultrasonic probe distance H transmitting and receiving the distance of propagating in the middle of theprocess₁2 times, so H₁Size by ultrasonic velocity and transmission time t decision, shown in following formula:

H₁＝C*t/2；

Suppose that herein the aerial velocity of propagation of sound wave is a fixing value, such as 340m/s, i.e. C=340m/s, time t is determined by the threshold value echo discriminant approach in the above-mentioned existing conventional ultrasonic liquid-level measurement.Because ultrasonic probe is predetermined definite value apart from the height H of container bottom, so can calculate the height H of liquid level to container bottom₂:

H₂＝H-H₁；

But, in actual environment for use, the temperature of medium, pressure etc. may change, and the value that causes the velocity of sound is definite value 340m/s not necessarily, and the said method supposition velocity of sound is constant definite value, and this obviously can cause measuring error very greatly under the situation that actual environment for use changes.In addition, above-mentioned prior art determines that just there is bigger error in the conventional threshold value discriminant approach of time itself.

The technology of another kind of existing measuring liquid level, as document 2: disclosed technology in " ultrasonic application in measurement; Yin Xuquan; Zhang Jianhua; Gao Shouwei; Wang Zhongmin, modern electronic technology, total the 148th phase of 2003 the 5th phases ", as shown in Figure 2, the document has been set forth basic supersonic sounding principle, places two probes with the technology difference in the document 1 above fluid to be measured, and one is used for emission, one is used for receiving, but measuring method is the same with document 1, supposes that equally the velocity of sound is constant definite value, obviously this technology also can cause measuring inaccurate.

Therefore, wish to have supersonic level gauge and the method that a kind of Installation and Debugging are convenient, Maintenance and Repair are simple, precision is high, performance is good and be not counted in the velocity of sound.

Summary of the invention

The objective of the invention is to overcome and to count the velocity of sound in the prior art and only rely on the threshold value discriminant approach to determine that the travel-time has the shortcoming than mistake, a kind of device and method of improved ultrasonic measuring liquid level is provided.

To achieve these goals, the present invention takes following technical scheme:

A kind of device of ultrasonic measurement liquid level comprises:

One signal generator; One data collector; One data processing equipment; It is characterized in that, comprise that also a ultrasound emission probe and at least two ultrasonic receiving transducers are fixed on the probe fixing device, described ultrasound emission probe and at least two ultrasonic receiving transducers are on described probe fixing device in the plane, and wherein said ultrasound emission probe is connected with described signal generator with described ultrasonic receiving transducer; Described ultrasound emission probe is used for to liquid level direction emission ultrasound wave, described ultrasonic receiving transducer is used to receive the ultrasound wave that liquid level fires back, and ultrasonic signal is converted to electric signal is input in the described data collector, determine the travel-time of each receiving transducer received signal; Described data collector is connected with described data processing equipment, and liquid level data handled and obtain by described data processing equipment to data.

Further, the first ultrasonic receiving transducer forms first distance between described ultrasound emission probe, and the described second ultrasonic receiving transducer forms second distance between described ultrasound emission probe, and described first distance does not wait with described second distance.

Further, described second distance is greater than described first distance.

Further, the line between each described ultrasonic probe is a straight line, and this straight line is parallel with liquid level.

Further, described probe fixing device has a movable part, and this movable part can be regulated the distance between each described ultrasonic probe, to adapt to the practical measurement requirement of different bores.

Further, this device comprises that also an input media is connected with described data processing equipment, is used to import the distance of each described ultrasonic probe to the bottom of tested liquid.

Further, also comprise an output unit, be used for output and display result.

A kind of method of ultrasonic measuring liquid level may further comprise the steps:

1) provide a ultrasound emission probe to liquid level emission ultrasound wave;

2) provide at least two ultrasonic receiving transducers to receive the ultrasound wave that reflects from tested liquid level;

3) write down ultrasound wave respectively from being transmitted into the travel-time of reception;

4) determine the radial distance of each ultrasonic receiving transducer to described ultrasound emission probe; The pop one's head in fore-and-aft distance of bottom of tested liquid of described ultrasonic receiving transducer and described ultrasound emission;

5) radial distance and the described fore-and-aft distance by hyperacoustic travel-time and each ultrasonic receiving transducer obtains liquid level.

Further, measure the phase differential between each road echo received signal in the step 3), determine that accurately each road signal arrives the moment of receiving transducer.

Further, step 1) and step 2) in, all probes all are in the plane that is parallel to tested liquid level.

Further, all probes all are in the plane that is parallel to tested liquid level, and are arranged in a straight line.

Further, one of them ultrasonic receiving transducer is to close with the ultrasound emission probe to put described step 2).

Further, described step 2) ultrasonic receiving transducer is two in, and the travel-time of the two-way received signal that the first ultrasonic receiving transducer and the second ultrasonic receiving transducer record is respectively t₁And t₂, the first ultrasonic receiving transducer is different to the radial distance of ultrasound emission probe with the second ultrasonic receiving transducer, is respectively 2l₁With 2 (l₁+ l₂), the distance of the bottom surface of the tested liquid of popping one's head in is h, then liquid level is${\mathrm{<figure-callout\; label="h"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">h</figure-callout>}}_2=h-\sqrt{\frac{{(l_1+l_2)}^2{t_1}^2-{l_1}^2{{\mathrm{<figure-callout\; label="t"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}^2}{{{\mathrm{<figure-callout\; label="t"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}^2-{t_1}^2}}.$

Compared with prior art, the invention has the beneficial effects as follows:

The present invention need not consider the velocity of sound when calculating liquid level, nor be that single dependence threshold value diagnostic method is determined acoustic transit time, so in the actual environment for use, even the also accurate measuring liquid level of variation that the temperature of medium, pressure etc. change and causes the velocity of sound, the present invention contrasts the precision that classic method has effectively improved level gauging.

Description of drawings

Fig. 1 is the ultrasonic liquid level measuring instrument fundamental diagram of prior art;

Fig. 2 is the basic supersonic sounding schematic diagram of prior art;

Fig. 3 is the embodiments of the invention synoptic diagram.

Drawing is described as follows:

The 1-signal generator, 2-ultrasound emission probe, the 3-first ultrasonic receiving transducer, the 4-second ultrasonic receiving transducer, 5-data collector 6-data processing equipment 7-probe fixing device

Embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:

The present invention places a plurality of probes on same plane on the liquid level, an emission ultrasound wave, the ultrasound wave that remaining reception fires back.Because the position difference that receiving transducer is placed, so the travel path difference of the sound wave that receives, just travel-time difference.Determine the travel-time of each receiving transducer received signal with data collector, thereby determine to propagate the angular relationship between the sound ray.Line between each probe, the propagation trajectories of sound ray etc. are coupled together, find the solution liquid level and just be equivalent to find the solution leg-of-mutton height.Distance between each probe is predefined definite value, and promptly leg-of-mutton base determines, sound ray and vertical direction angulation can determine by said method, leg-of-mutton higher position can in the hope of, thereby liquid level is just definite.

At first produce an electric signal by the signal generator, excitation ultrasound emission probe produces mechanical vibration emission ultrasound wave, and sonic propagation is during to the interface of air and liquid, owing to the two impedance difference is bigger, most of sound wave can reflect, and fraction can continue to propagate forward.Echo from the liquid level reflection enters data acquisition system (DAS) after two or more receiving transducers convert electric signal to, by software of calculation, determine the concrete travel-time of each road signal.Distance between each probe is the predetermined definite value of measurement mechanism, according to the travel-time of each the road ultrasonic signal that obtains,, can draw again from the distance of the liquid level of popping one's head in through computing, the distance of container bottom of popping one's head in is a definite value, and liquid level has just been calculated.

The present invention is further described below in conjunction with accompanyingdrawing 3 and embodiment.

The device of this ultrasonic measurement liquid level comprises: signal generator 1;Data collector 5; Data processing equipment 6; 3,4, three ultrasonic probes ofultrasound emission 2 and two ultrasonic receiving transducer of probe are fixed on theprobe fixing device 7;Probe fixing device 7 usefulness steel plate materialses are made, and preferably, comprise a movable part on this stationary installation, and this movable part can be regulated the distance between each described ultrasonic probe, to adapt to the practical measurement requirement of different bores.During such as the liquid level in the container of measuring larger caliber, can regulate movable part and make the distance between each ultrasonic probe increase, correspondingly, regulate movable part in some cases and make the distance between each ultrasonic probe reduce to be convenient for measuring.

2 and twoultrasonic receiving transducers 3,4 of ultrasound emission probe are on described probe fixing device in the plane, and whereinultrasound emission probe 2 is connected with described signal generator 1, is used for launching ultrasound wave to the liquid level direction.Ultrasonic receivingtransducer 3,4 is used to receive the ultrasound wave that liquid level fires back, and ultrasonic signal is converted to electric signal is input in thedata collector 5, determines the travel-time of each receiving transducer received signal;Data collector 5 is connected with data processing equipment 6, and liquid level data is handled and obtained to 6 pairs of data of data processing equipment.Signal generator 1 adopts the SG1005 product of Sheng Pu company.Ultrasoundemission probe 2,ultrasonic receiving transducer 3 and 4 are the conventional products that sell in market.The conventional products thatdata collector 5 is sold for market is as the PCI-20612 of Sichuan company of Top production.Data processing equipment 6 is finished the processing of image data is calculated, calculate final liquid level data, conventional device such as processor, storer etc. that this device is sold for market connect to form according to the mode that the art technology people knows, and carry out computing according to computing formula disclosed by the invention.

As shown in Figure 3, the firstultrasonic receiving transducer 3 forms first distance betweenultrasound emission probe 2, count 2l₁The secondultrasonic receiving transducer 4 forms second distance betweenultrasound emission probe 2, count 2 (l₂+ l₁), certain first distance and second distance can be regulated before measurement according to actual needs by movable part, in case after determining, just no longer changed in measuring process.General first distance does not wait with second distance, and among Fig. 3, second distance is greater than first distance, and the line between emissionultrasonic probe 2, firstultrasonic receiving transducer 3, the secondultrasonic receiving transducer 4 is a straight line, and this straight line is parallel with liquid level.Certainly, among this Fig. 3, for convenience, line between emissionultrasonic probe 2, firstultrasonic receiving transducer 3, the secondultrasonic receiving transducer 4 is a straight line, in fact the three can need only the firstultrasonic receiving transducer 3 and the corresponding respectively sound ray a of the secondultrasonic receiving transducer 4 not point-blank₁And a₂The length difference makes two bundle ultrasound waves exist phase differential just when arriving ultrasonic receiving transducer, that is to say that two bundle ultrasound waves arrive separately ultrasonic receiving transducer respectively with the different transmission times.

This device comprises that also an input media is connected with described data processing equipment, is used to import the distance of each ultrasonic probe to the bottom of tested liquid.This input media can adopt keyboard.

Present embodiment also comprises an output unit, is used for output and display result, such as the display that adopts a prior art.

When adopting the foregoing description measurement device liquid level, with emissionultrasonic probe 2, firstultrasonic receiving transducer 3, the secondultrasonic receiving transducer 4 by probe fixing device be fixed on liquid level directly over, make emissionultrasonic probe 2, first ultrasonic receivingtransducer 3, the secondultrasonic receiving transducer 4 all equate to the vertical distance of liquid level.As shown in Figure 3, h is a container height, launches the distance ofultrasonic probe 2, firstultrasonic receiving transducer 3, the secondultrasonic receiving transducer 4 to liquid bottom exactly, is predetermined definite value before measuring; h₁Be the height of emissionultrasonic probe 2, firstultrasonic receiving transducer 3, the second ultrasonic receivingtransducer 4 to liquid level; h₂Be the distance of liquid level to container bottom.l₁Be half of distance between emissionultrasonic probe 2 to the firstultrasonic receiving transducers 3, l₂Be half of distance between first ultrasonic receivingtransducer 3 to the second ultrasonic receiving transducers 4.a₁Be emissionultrasonic probe 2 emission ultrasound waves, sound ray from emissionultrasonic probe 2 to liquid level when the firstultrasonic receiving transducer 3 receives, a₂Be emissionultrasonic probe 2 emission ultrasound waves, sound ray from emissionultrasonic probe 2 to liquid level when the second ultrasonicreceiving transducer 4 receives, θ₁Be a₁With h₁Between angle, sound ray a just₁And the angle between the vertical direction; θ₂Be a₂With h₁Between angle, sound ray a just₂And the angle between the vertical direction.

By data collector, can calculate ultrasound wave at a₁And a₂Propagating the used time on the path, is respectively t₁And t₂Because the initial vibration of signal constantly is not easy to determine, so the present invention is by measuring the phase differential between the two paths of signals, accurately draw the mistiming between the two paths of signals due in, determine that such as the threshold value that adopts prior art method learns that the due in of first via signal is t₁, learn that by the phase differential between the two paths of signals mistiming between the second road signal and the first via signal is Δ t, thereby the due in of learning the second road signal is t₂=t₁+ Δ t.The present invention has adopted the phase differential of measuring two paths of signals to determine the two paths of signals travel-time, and is more accurate than the travel-time of definite one road ultrasonic signal of the initial moment of in the prior art signal.Phase differential in the present embodiment between the two paths of signals is to determine by two ultrasonic probes of prior art and data collector.

If ultrasonic velocity of propagation in same medium is c, then:

$\frac{l_1}{c\&times;t_1}=\sin {\mathrm{\&theta;}}_1;$$\frac{l_1+l_2}{c\&times;{\mathrm{<figure-callout\; label="t"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}=\sin {\mathrm{\&theta;}}_2;$$\frac{l_1}{h_1}=\tan {\mathrm{\&theta;}}_1;$$\frac{l_1+l_2}{h_1}=\tan {\mathrm{\&theta;}}_2$

Because l₁, l₂, t₁, t₂All be known, so just can calculate θ₁And θ₂Value, thereby calculate h₁Value, and h also is known, the height h of liquid level₂Just draw:${\mathrm{<figure-callout\; label="h"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">h</figure-callout>}}_2=h-h_1=h-\sqrt{\frac{{(l_1+l_2)}^2{t_1}^2-{l_1}^2{{\mathrm{<figure-callout\; label="t"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}^2}{{{\mathrm{<figure-callout\; label="t"\; filenames="A20061008953900111.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}^2-{t_1}^2}}.$Can, the present invention need not consider the velocity of sound when calculating liquid level, nor be that single dependence threshold value diagnostic method is determined acoustic transit time, so in the actual environment for use, even the also accurate measuring liquid level of variation that the temperature of medium, pressure etc. change and causes the velocity of sound, the present invention contrasts the precision that classic method has effectively improved level gauging.

It should be noted last that above embodiment is only unrestricted in order to technical scheme of the present invention to be described.Although the present invention is had been described in detail with reference to embodiment, those of ordinary skill in the art is to be understood that, technical scheme of the present invention is made amendment or is equal to replacement, do not break away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (13)

1, a kind of device of ultrasonic measurement liquid level comprises:

One signal generator; One data collector; One data processing equipment;

It is characterized in that, comprise that also a ultrasound emission probe and at least two ultrasonic receiving transducers are fixed on the probe fixing device, described ultrasound emission probe and at least two ultrasonic receiving transducers are on described probe fixing device in the plane, and wherein said ultrasound emission probe is connected with described signal generator with described ultrasonic receiving transducer; Described ultrasound emission probe is to liquid level direction emission ultrasound wave, described ultrasonic receiving transducer receives the ultrasound wave that liquid level fires back and ultrasonic signal is converted to electric signal and is input in the described data collector, and described data collector is determined the travel-time of each receiving transducer received signal; Described data collector is connected with described data processing equipment, and liquid level data handled and obtain by described data processing equipment to data.

2, according to the device of the described ultrasonic measurement liquid level of claim 1, it is characterized in that, the first ultrasonic receiving transducer forms first distance between described ultrasound emission probe, the described second ultrasonic receiving transducer forms second distance between described ultrasound emission probe, described first distance does not wait with described second distance.

According to the device of the described ultrasonic measurement liquid level of claim 2, it is characterized in that 3, described second distance is greater than described first distance.

According to the device of the described ultrasonic measurement liquid level of claim 1, it is characterized in that 4, the line between each described ultrasonic probe is a straight line, and this straight line is parallel with liquid level.

According to the device of the described ultrasonic measurement liquid level of claim 1, it is characterized in that 5, described probe fixing device has a movable part, regulate distance between each described ultrasonic probe by this movable part.

6, according to the device of the described ultrasonic measurement liquid level of claim 1, it is characterized in that, comprise that also an input media is connected with described data processing equipment.

7, according to the device of each described ultrasonic measurement liquid level of claim 1-6, it is characterized in that, also comprise an output unit, be used for output and display result.

8, a kind of method of ultrasonic measuring liquid level may further comprise the steps:

1) provide a ultrasound emission probe to liquid level emission ultrasound wave;

2) provide at least two ultrasonic receiving transducers to receive the ultrasound wave that reflects from tested liquid level;

3) write down each road ultrasound wave respectively from being transmitted into the travel-time of reception;

4) determine the radial distance of each ultrasonic receiving transducer to described ultrasound emission probe; The pop one's head in fore-and-aft distance of bottom of tested liquid of described ultrasonic receiving transducer and described ultrasound emission;

5) radial distance and the described fore-and-aft distance by hyperacoustic travel-time and each ultrasonic receiving transducer obtains liquid level.

9, the method for described according to Claim 8 ultrasonic measurement liquid level is characterized in that, determines that by the phase differential of measuring between each road echo received signal each road signal arrives the moment of receiving transducer in step 3).

10, the method for described according to Claim 8 ultrasonic measurement liquid level is characterized in that, in step 1) and step 2) in, all probes all are in the plane that is parallel to tested liquid level.

According to the method for the described ultrasonic measurement liquid level of claim 10, it is characterized in that 11, all probes all are in the plane that is parallel to tested liquid level, and are arranged in a straight line.

12, the method for described according to Claim 8 ultrasonic measurement liquid level is characterized in that, described step 2) in one of them ultrasonic receiving transducer and ultrasound emission probe close and put.

13, the method for described according to Claim 8 ultrasonic measurement liquid level is characterized in that, described step 2) in, the travel-time of the two-way received signal that the first ultrasonic receiving transducer and the second ultrasonic receiving transducer record is respectively t₁And t₂, the first ultrasonic receiving transducer is different to the radial distance of ultrasound emission probe with the second ultrasonic receiving transducer, respectively

Be 2l₁With 2 (l₁+ l₂), the distance of the bottom surface of the tested liquid of popping one's head in is h, liquid level is:

$h_2=h-\sqrt{\frac{{(l_1+l_2)}^2{t_1}^2-{l_1}^2{t_2}^2}{{t_2}^2-{t_1}^2}}.$

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