CN1045658C - Time gate ultrasonic sensor and method - Google Patents
Time gate ultrasonic sensor and method Download PDFInfo
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- CN1045658C CN1045658C CN91112613A CN91112613A CN1045658C CN 1045658 C CN1045658 C CN 1045658C CN 91112613 A CN91112613 A CN 91112613A CN 91112613 A CN91112613 A CN 91112613A CN 1045658 C CN1045658 C CN 1045658C
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
- G01F25/0092—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume for metering by volume
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/296—Acoustic waves
- G01F23/2961—Acoustic waves for discrete levels
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- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/296—Acoustic waves
- G01F23/2962—Measuring transit time of reflected waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/02—Analysing fluids
- G01N29/024—Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
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- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
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- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02818—Density, viscosity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02836—Flow rate, liquid level
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Abstract
A time gate ultrasonic sensor measures a physical property of a material, such as the presence of the material, within a defined space. The sensor includes at least one transducer connected to a support structure and positioned generally adjacent the defined space for transmitting and receiving ultrasonic signals across the defined space. The ultrasonic signals include a main waveform which travels across the defined space and a self-test waveform which travels along the support structure. The sensor monitors the received ultrasonic signals during a main time window to sense whether the main waveform is present in the received signals. The sensor performs a self-test each measurement cycle by determining whether the self-test waveform is present during a self-test time window.
Description
The present invention relates to a kind of be used for survey giving whether have material to exist in the fixed gap.
Existing various ranging systems and ultrasonic level gauging system.At United States Patent (USP) 4,815, proposed a kind of " echo ranging " ultrasonic transducer in 323 sending ultrasonic signal such as, Ellinger etc., its liquid level reflected back in the aviation fuel case is also detected.From measured the come out two-way time that sends to reception, and calculate the amount and the density of fuel by central processing unit according to the data of two-way time and storage.
At United States Patent (USP) 4,299, in 114 the another kind of ultrasonic detector, Silvermetz etc. have proposed by sending and receive the feedback loop closure that ultrasound-transmissive between ultrasonic transducer makes a circuit, and give when quantitative this circuit oscillation when feeding back to be increased to.Install to send and during the position of receiving transducer when the material plane in the container rises to, the higher feedback quantity by this material makes circuit play shake.Could steady operation when feedback quantity when this type requires liquid is arranged and the difference between airborne feedback quantity are big.Also can reduce degree of stability by the bad feedback in the detector body.If captured air in the material, also can make the feedback reduction and make and survey failure.This class detector is general bigger, and the Unite States Standard (USS) conical screw hole apertures such as (NPT) that is not suitable for by 3/4 inch inserts in the container.In this class detector, the transducer calibration error also can reduce to make the detection failure by the feedback of material.
Ultrasonic detector also can detect back-to-back to be installed an additional crystal (transducer) and tests oneself on (reception) crystal.Driving should additional crystal, so that the excitation receiving crystal is to realize feedback, the function that can test receiving crystal like this when not having measured material in air gap.This fully test probe detect detectivity when in the air gap measured material being arranged because it can not detect the situation that crystal breaks away from detector body fully.And this arrangement has increased the complicacy of total volume and detector and wiring.
Silvermetz etc. are at United States Patent (USP) 4,299, have invented the another kind configuration of testing oneself in 114: under test mode, the ultrasonic system monitoring sends between crystal and receiving crystal the ultrasound-transmissive by a supporting construction.These crystal are connected in the feedback loop of an oscillator, its starting of oscillation when system can work.Amplitude of the ultrasonic signal that it is propagated by supporting construction is enough to keep vibration and just thinks that system can work.But when detector is to use plastic supporting structure, this configuration just is difficult for fine work, because weak feedback falls in the decay in the plastics, and it keeps the vibration difficulty.
The United States Patent (USP) of Dam discloses a system that the interior liquid of detection receptacle exists for No. 4630245, surveys main waveform in the time of reception window, is digitized into pulse train then and is counted.The patent of Dam has also been announced the feature of testing oneself, and wherein closed switch makes the time of reception window move forward in time to cancel a time-delay like this, with the signal of testing oneself of reception reflection, rather than main waveform.When testing oneself, system is operated in the regular detection mode.
The United States Patent (USP) of Kikuta etc. discloses the ultrasonic liquid-level measurement instrument No. 4909080, based on the transmission of ultrasonic signals time of launching and returning to liquid level, measures the liquid level in the storage tank.
The present invention relates to detection method and time gate ultrasonic detector with automatic self-test function, it measures the physical property of certain material in this spacing according to the speed of ultrasonic signal when giving determining deviation.Such as, there is no liquid to survey liquid level position in the container in the determining deviation by detect giving.
This ultrasonic detector comprise at least one link to each other with supporting construction and with the adjoining ultrasonic transducer of predetermined gap so that send and receive ultrasonic signal.This ultrasonic signal comprises main waveform of propagating by predetermined gap and the waveform of propagating along supporting construction of testing oneself.The ultrasonic signal that detector monitors is received, so that check whether there is main waveform in the received signal in main time window, and whether monitoring exists the waveform of testing oneself in the time window of testing oneself.This detector according in main time window, whether exist main waveform detect to fixed gap in the physical characteristics of material, he can be that various solids, slurry, foam or other are handled material.Whether this detector also exists the waveform of testing oneself to determine whether detector operation is normal according to the time window of testing oneself.
Usually, the propagation of ultrasonic signal in liquid can be air or certain processing gas than fast at gas, and faster than liquid again in solid.In one embodiment, whether detector has liquid to detect the height of liquid level by measuring to give in the fixed gap.It is to depend on that ultrasonic signal is to propagate or propagate by gas by liquid that main waveform is arranged in the main window, because their velocity of propagation difference.If in the main window main waveform is arranged, then ultrasonic signal is propagated by liquid.If not main waveform in the main window, then ultrasonic signal is propagated by gas, because of at this moment receiving the main waveform requirement long period.
This detector can be measured the height of the density and the material face of material simultaneously, because signal is relevant with the density of material by the time of material.In this embodiment, its time window can be adjusted to the density of not only test material but also detect and have or not measured material in the air gap.If know the density of two kinds of materials, the interface location of two kinds of materials in the also detectable air gap of this ultrasonic detector.
In yet another embodiment, ultrasonic detector comprises that one sends a transducer and a receiving transducer, is a predetermined gap therebetween.Supporting construction is made up of the cramp bar or the some cramp bars that send between transducer and the receiving transducer.In another embodiment, supporting construction is a kind of vessel or pipe, and it has a circumferential wall and an inside diameter, and it has determined (sending out between the receipts transducer) gap.Send transducer and link to each other with vessel wall, be sent to receiving transducer so that ultrasonic signal can pass this gap from the transmission transducer with receiving transducer.
In another embodiment, this ultrasonic detector comprises single transducer, and it had not only sent but also received ultrasonic signal.In this embodiment, supporting construction is a ultrasonic reflection face that faces by gap and this transducer, so that the ultrasonic signal that produces from transducer arrives this reflecting surface by this gap, turns back to this transducer again.This reflecting surface can have the surface of a concave, and its curvature should be chosen to and can deliver to this transducer the signal focus of reflection and by this gap.In supporting construction is in the embodiment of a container or pipe, and this single transducer should receive chamber wall so that the ultrasonic signal that sends from transducer can pass chamber wall and this transducer of reflected back that interior diameter arrives and transducer faces toward.
The method accurately and reliably of utilizing the waveform of propagating in supporting construction of testing oneself to test this ultrasonic detector functional completeness also is provided in the time gate configuration of the present invention.Because general ultrasonic propagation in solid is than at liquid and fast in gas, because supporting construction is a solid material, so first waveform that receives is the waveform of propagating along supporting construction of testing oneself.Second waveform receiving is to pass the main waveform that propagate in the gap.To each total waveform of testing oneself that exists that transmits.
The ultrasonic signal of receiving during the predetermined time window of testing oneself of this detector monitors tests oneself whether there is the waveform of testing oneself in the time window with detection.Whether normally whether the waveform of testing oneself exists is probe functionality sign, and this method can be tested the function of each transducer and the ability that transducer detects the liquid that passes the gap.If receiving transducer breaks away from supporting construction, because can not passing supporting construction, do not propagate the waveform of testing oneself, this inefficacy will be detected.Even the processing material is in the gap and do not have additional back-to-back transducer to test transmission and receiving transducer respectively, also can test oneself continuously.This method has reduced the complicacy and the size of whole detector.
Fig. 1 is the cut-open view according to time gate ultrasonic detector of the present invention.
Fig. 2 is the cut-open view attached to the time gate ultrasonic detector on the pipe of the present invention.
Fig. 3 has provided the received main waveform of ultrasonic detector illustrated in figures 1 and 2 and the waveform of testing oneself.
Fig. 4 is the electrical schematic diagram of ultrasonic detector of the present invention.
Fig. 5 is the waveform of ultrasonic detector circuit each point signal shown in Figure 4.
Fig. 6 is the main wave test pulse in the supersonic sounding circuit shown in Figure 4 and the time diagram of the wave test pulse of testing oneself.
Fig. 7 is the sectional view of monocrystal ultrasonic detector of the present invention.
The present invention is a kind of time gate ultrasonic detector, when this detector is checked by surveying the main waveform propagated in the gap and by testing oneself during waveform that detector body is propagated, survey the physical characteristics of measured material in the predetermined gap with the received ultrasonic signal of gate receiving crystal during time of appointment or " window ".Have or not measured material in the gap that has the dereliction waveform table to show in the main window, in the time window of testing oneself, have or not the waveform of testing oneself to represent then whether the function of this detector is normal.
Fig. 1 is the sectional view of ultrasonic detector of the present invention.Detector 10 comprises supporting construction 12.Ultrasonic transmission transducer (crystal) 14 and ultrasonic receiving transducer (crystal) 16.Supporting construction 12 comprises abutment wall 18 and gap 20.Abutment wall 18 is also referred to as bridge.Transducer 14 and 16 is installed on the supporting construction 12 so that they can send and receive ultrasonic signal by gap 20 and along abutment wall 18.Supporting construction 12 can be made such as metal or plastics with various materials.In a kind of typical structure, transducer 14 and 16 is installed in a pair of cavity on the structure 12 that is fastened to half hull shape on the abutment wall 18.Abutment wall 18 is made by solid metal or plastics, flutedly above it 36 passes through so that go between.Then whole detector 13 sealings.
Send transducer 14 and link transmitter 30 by electric wire 32.Transmitter 30 periodically provides electronics to send pulse and arrives transducer 14 by electric wire 32.Send when sending pulse to sending transducer 14 when transmitter 30, this pulse just encourages transducer 14, makes transducer resonance on its free-running frequency.Transducer 14 sends the ultrasonic signal of propagating by gap 20 and abutment wall 18.20 ultrasonic signals of propagating are called main waveform through the gap, and the signal of propagating through abutment wall 18 claims the waveform of testing oneself.
Receiving transducer 16 is received receiver 34 by electric wire 36.Receiving transducer 16 becomes electric signal to ultrasonic signal 22 and is added on the lead-in wire 36.
The density of passing material in ultrasonic signal 22 that gap 20 absorbed and the gap is inversely proportional to.Therefore, when in the gap 20 during no liquid, the decay when there is liquid in the decay of main waveform in the gap.High frequency is such as several kilo hertzs of sesames or when higher, and it is big especially to decay.When the gap was empty, the signal of propagating by the gap was zero-signal basically.When the full of liquid of gap, transducer 16 receives main waveform.Main waveform makes transducer 16 resonance and produce electric signal on lead-in wire 36.Like this, whether the main waveform on the receiving transducer 16 exists and just represents in the gap 20 no liquid is arranged.
Each is sent the total existence of pulse pass the ultrasonic signal 22 (waveform of testing oneself) of abutment wall 18.This signal can be used for self-test function.Do not have or not measured material all can test oneself continuously in the ligament 20.This self-test function will go through in the back.
Detector 10 can be in order to the physical characteristics of material in the measurement clearance 20.Such as, can no liquid be arranged by surveying in the gap 20, and measure the interior liquid level position of a container with detector 10.Detector 10 can be fastened on the flange fit engagement part, such as standard N PT3/4 inch joint.Then this joint is fastened on the chamber wall that comprises measured material.To describe in detail as the back, detector of the present invention can be done to such an extent that can put in the very little accessory, make it very big dirigibility be arranged to be suitable for various uses.
Time gate ultrasonic detector of the present invention and not requiring sends receiving transducer and must link on as shown in Figure 1 the detector commonly used " supporting arm ".These two transducers can be made respectively, as long as certain structure that they can be produced the waveform of testing oneself links to each other, can be installed in them on the container or pipe of the Any shape that any material of any wall thickness constitutes like this, as long as send and receiving transducer is mounted as shown in Figure 2 faces toward mutually.
Fig. 2 be according to the present invention ultrasonic detector attached to the cut-open view on the pipe.Send on the wall 43 that transducer 40 and receiving transducer 42 be installed in pipe 44 so that they face one another.Pipe 44 comprises each internal diameter 46, and it is called " gap ".Main waveform 48 passes to receiving transducer 42 along internal diameter 46 from sending transducer 40.The waveform 50 of testing oneself passes to receiving transducer 42 along circumferential wall 43 from sending transducer 40.Similar with the supporting arm 18 of Fig. 1, wall 43 plays supporting arm.Gu and wall 43 has substituted supporting arm 18.
Fig. 3 is the receiving transducer 16 among Fig. 1 and Fig. 2 and the time diagram of the 42 received main waveforms and the waveform of testing oneself, and it has illustrated the amplitude and the time relation of the ultrasonic signal that receives.The propagation of ultrasonic signal in liquid be than fast in gas, and propagate in solid again than fast in the liquid.So 20 speed of propagating depend on whether have liquid to have (being the liquid side height) in this gap to ultrasonic signal 22 along the gap.Because ultrasonic signal is propagated in solid than fast in liquid, first signal that receives is the signal of propagating along abutment wall (or supporting arm) 60 of testing oneself.Second received signal is to pass the main waveform 62 that the liquid in the gap transmits.The amplitude of signal 60 of testing oneself levels off to zero after its peak amplitude D0 that this signal arrives for the first time.Be owing to repeatedly reflect the waveform subsequent 64a of generation to 64f after the main waveform 62 along the gap.Waveform 66 expressions shown in the dotted line are passed air (no liquid in the gap) and are transmitted the signal that is received.Compare with 64a～64f with the waveform 62 that transmits by liquid, the arrival of waveform 66 is quite slow and amplitude is quite little.
In the used in the prior art vibration type ultrasonic detector, transmission and receiving transducer are received in the feedback loop, and when not handling material in the gap, this ring is stable, and this is called " doing " condition.When material entered this gap, this circuit entered oscillatory regime, and this is called " wetting " condition.The design of this vibration type exist meet among many present invention less than problem.At first this doing/wet signal ratio may not be even as big as making the degree of its steady operation.This may be because the too many signal supporting arm by detector passes away, or since aerial decay only decay in the material is big to be caused than handling slightly.Secondly, the consistance of measured material also can influence the performance of detector.If in the material the very highdensity air that is wrapped in is arranged, circuit can not starting of oscillation.
Among the present invention, in the time will measuring liquid level position, just measure the amplitude of main signal at main time window, and from the signal that supporting arm comes be in another time (according to pass the time delay of supporting arm or before main time window or thereafter), thereby do not exist and interfere with each other.This supporting arm is not necessarily straight, also can be " U " type, the screwed pipe shape or other more microscler shape forming long ultrasonic path, the waveform delay of testing oneself is arrived after the main waveform.On the other hand, when density measurement, tested parameter is the time, rather than amplitude.And unlike prior art, keep vibration with amplitude." doing/wet " of its equivalence is quite higher than always.This has improved q﹠r greatly.The doing of its equivalence/wet is the amplitude W1 of " wet " signal 62 of propagating by the measured material in the gap than W1/D1, with the ratio of the amplitude D1 of " doing " signal 60 of the supporting arm propagation by detector when receiving this wet signal 62.Because at this moment the signal 60 than the initial arrival of propagating by the detector supporting arm postpones a lot, its amplitude C1 is also much smaller than its peak amplitude D0.Approach very much peak amplitude DO if pass first signal of gap reception, the signal of available this back reflection obtains bigger equivalence and " does/wet " ratio.The doing of vibration type ultrasonic detector/wet than being W1/D0, it is less than W1/D1.
Fig. 4 is the principle of compositionality figure of time gate ultrasonic detector of the present invention.This circuit comprises detector 10, transmitter 30, receiver 34, time gate piece 70, main wave test/comparison block 72, the wave test/comparison block 74 of testing oneself, main integral of pulse shape piece 76 and the integral of pulse shape piece 78 of testing oneself.Time gate piece 70 produces enabling signals, it certain hour " gate " detections/comparison block 72 and 74 to open window so that integration piece 76 and 78 seek main waveform that receivers 34 receive and test oneself waveform.Integration piece 76 and 78 provides and goes out 80 and 82, and whether they be illustrated respectively in its corresponding time window the main waveform and the waveform of testing oneself.Whether main waveform exists in the gap 20 of representing detector 10 whether liquid is arranged.Whether the waveform of testing oneself exists represents whether detector 10 is intact.The amplitude of waveform of testing oneself can be in order to measure the degree of degeneration of detector quality.
Detector 10 comprises transmission transducer 14 and receiving transducer 16.Transmitter 30 is connected and sends between transducer 14 and the time gate piece 70.Transmitter 30 comprises a pierce circuit, and the typical repetition frequency of its work is from 10 hertz to 5 kilo hertzs.Each cycle oscillator, transmitter 30 usefulness are that 25 volts the transmission pulse in transmission transducer nature transmission cycle of 1/4 to 1/2 encourages transmission transducer 14 perdurability.This transmission pulse makes and sends transducer resonance, and produces the ultrasonic signal 22 that passes gap 20 and the propagation of supporting arm 18 (see figure 1)s.This ultrasonic signal 22 is received transducer 16 and receives.Receiving transducer 16 is added to Hi-pass filter 84 to the electric signal that characterizes ultrasonic signal 22.Hi-pass filter 84 is given amplifier 86 signal of filtering.In amplifier output 88 are the filtering signals that amplified.
The time gate window is to be produced by the rising edge (Fig. 4) of time gate piece 70 according to the transmission pulse of transmitter 30 generations.Time gate piece 70 comprises capacitor C1, C2 and C3, resistance R 1, R2 and R3 and phase inverter I
1, I
2, I
3And I
4Form.Capacitor C1 links between transmitter 30 and the phase inverter I1.Resistance R 1 is connected on ground wire 90 and capacitor C1 and phase inverter I
1Node between.Resistance R 1 is a variable resistor, and its center tap 92 is received capacitor C 1 and phase inverter I
1Node on.Phase inverter I
1Output produce main waveform enabling signal.
Capacitor C 2 is connected on transmitter 30 and phase inverter I
2Resistance R 2 link with capacitor C 2 and phase inverter I
2Between node between.Resistance R 2 is variable resistors, and its center tap is received capacitor C 2 and phase inverter I
2Node on.Phase inverter I
2To go out be to send pulse prohibiting signal.
Capacitor C 3 is received between transmitter 30 and the phase inverter I3.Resistance R 3 is received between the node of ground wire 90 and capacitor C 3 and phase inverter I3.Resistance R 3 is variable resistors, and its center tap is received on the node between capacitor C 3 and the phase inverter I3.Phase inverter I3 receives going out of phase inverter I3.The output of phase inverter I4 produces the waveform gate-control signal of testing oneself.
Each sends the rising edge 98 of pulse by three RC time constant integrations of time gate integrator 70.Capacitor C 1 and resistance R 1 form first time constant, and it controls the duration of main waveform enabling signal, and this signal is that high level is effective.Capacitor C 2 and resistance R 2 form second time constant, and its control sends the effective time span of pulse prohibiting signal.Capacitor C 3 and resistance R 3 form the 3rd time constant, and its controls the duration of the waveform enabling signal effective status of testing oneself.These signals will illustrate in Fig. 5.
Fig. 5 has the time diagram of the time gate ultrasonic detector of short supporting arm in a transmitter each signal waveform in 30 cycles.Signal amplitude and time relation have been the figure shows.The output 88 of amplifier is shown in this figure topmost.First waveform that arrives is to send pulse waveform 100.This waveform sends transducer 14 and produces when its starting oscillation.Because the propagation of ultrasonic signal in solid is than at liquid and fast in gas, the waveform of second arrival is to pass the waveform 102 of testing oneself that detector supporting arm 18 is propagated.The waveform of the 3rd arrival is to pass the main waveform 104 that the liquid in the detector gap 20 is propagated.The waveform of the 4th arrival is the echoed signal that reflects the main waveform 104 that causes by gap 20.
Send pulse prohibiting signal 110 and test oneself waveform enabling signal 108 after Sheffer stroke gate 114 (Fig. 4) is carried out the logical and not operation, produce the time window 116 (Fig. 5) of testing oneself.The selection of time window 116 of testing oneself makes the detection/comparer 74 of testing oneself can detect the existence of the waveform 102 of testing oneself in the time window 116 of testing oneself.Having the waveform 102 of testing oneself in the time window 116 of testing oneself is that probe functionality indicates normally.Test oneself and do not have the waveform 102 expression detector cisco unity malfunctions of testing oneself in the time window 116.
Main wave test/comparison block 72 is received between amplifier 86 and the main integral of pulse shape device piece 76.Piece 72 comprises resistance R 4, comparer 122 and Sheffer stroke gate 118.Resistance R 4 be connected on voltage source V+and ground wire 90 between.The center tap 124 of variable resistor R4 connects the noninverting input of comparer 122.The anti-phase input of comparer 122 connects the output 88 of amplifier.Sheffer stroke gate 118 is received in the output of comparer 122.Sheffer stroke gate 118 produces main wave test output 126.
Center tap 124 provides a threshold voltage for the noninverting input of comparer 122.Comparer 122 is compared the amplitude of amplifier output 88 with this main waveform threshold voltage.Main waveform threshold voltage is set by the center tap 124 of regulating resistance R 4.The adjusting of this threshold voltage desired main waveform 104 (Fig. 5) amplitude occurs during should making main waveform time gate window 120.This value with the physical property of measured material in the size of used type photodetector, excitation frequency, detector, the gap with amplifier 86 gains and different.The output of comparer 122 is received Sheffer stroke gate 118 with main waveform enabling signal 112 and transmission pulse prohibiting signal, so that only detect main waveform 104 during main waveform time gate window 120.
Wave test/the comparator block of testing oneself 74 is received amplifier 86 and is tested oneself between the integral of pulse shape piece 78.Piece 74 comprises resistance R 5, comparer 128 and Sheffer stroke gate 114.Resistance R 5 receive voltage source V+and ground 90 between.The center tap 130 of this variable resistor R5 connects the non-inverting input of comparer 128.Amplifier output 88 connects the inverting input of comparer 128.Sheffer stroke gate 114 is received in the output of comparer 128.Sheffer stroke gate 114 produces the wave test output 132 of testing oneself.
The center tap 130 of resistance R 5 produces the waveform threshold voltage of testing oneself.This waveform threshold voltage of testing oneself can be adjusted by regulating center tap 130, so that the amplitude of waveform 102 for expectation of testing oneself in the waveform time gate window 116 of testing oneself.The amplitude and the threshold voltage of testing oneself of amplifier output 88 compare at comparer 128.The output of comparer 128 and the waveform enabling signal 108 and send pulse prohibiting signal 110 and deliver to Sheffer stroke gate 114 together of testing oneself are so that only detect the waveform 102 of testing oneself during the time gate window 116 of testing oneself.
Fig. 6 has provided the time diagram of the main wave test output 126 and the wave test output 132 of testing oneself of short supporting arm detector.Fig. 6 has represented the amplitude and the time relation of detecting device waveform 126 and 132.Supporting arm to long arrives behind the comparable main waveform of the waveform of testing oneself.The main waveshape detector output 126 a series of pulses 134 that comprise corresponding to main waveform 104 (Fig. 5) also comprise a series of pulses 136 corresponding to echo 106.The waveshape detector of testing oneself output 132 pulse trains 138 that comprise corresponding to the waveform 102 (Fig. 5) of testing oneself.There is train of impulses 134 to be illustrated in the main waveform time gate window 120 in main waveshape detector output 132 main waveform 104 is arranged.Equally, the current detector output 132 of testing oneself has train of impulses 138 to be illustrated in to test oneself the waveform 102 of testing oneself in the waveform time gate window 116.
Main wave table detecting device output 126 is by main integral of pulse shape device piece 76 integrations.The waveform wave detector of testing oneself output 132 is by integral of pulse shape device piece 78 integrations of testing oneself.Piece 76 comprises phase inverter 15, main waveform counter and holding circuit 140 and main waveform relay driver 142.Phase inverter I5 is connected between Sheffer stroke gate 118 and main waveform counting and the holding circuit 140.Main waveform counting and holding circuit 140 are between I5 and the main waveform relay driver 142.The step-by-step counting that main waveform counting and holding circuit 140 were received Sheffer stroke gate 118 in the oscillation period of each transmitter 30.When the umber of pulse of being counted in each oscillation period surpassed set-point (such as 3), counter just produced a signal in output 146, has main waveform with indication in main waveform time gate window 120.
Signal 146 is added to main waveform relay drive 142, produces main waveform output signal 80 by it.Main waveform counting and holding circuit 140 have the input 148 that resets, and it receives transmitter 30.Send the beginning in cycle in each of transmitter 30, transmitter 30 provides a reset pulse that main number device and holding circuit 140 are resetted.By the number counting of paired pulses in the given extended period, the vacation that circuit 140 can be eliminated main waveform 104 detects.
As previously mentioned, second group pulse 136 among Fig. 6 is illustrated in the echo 106 (Fig. 5) in the detector gap.The echo 106 that main waveform threshold voltage can be adjusted in amplifier output 88 can not produce echo 106 in the output of main waveform counting and holding circuit 140.But this there is no need, because the state of counter will remain on given umber of pulse after each the detection, till being reset.
Equally, waveshape detector output 132 78 integrations of integral of pulse shape device piece of being tested oneself of testing oneself.Piece 78 comprises phase inverter I6, the waveform of testing oneself is counted and the holding circuit 150 and the waveform relay drive 152 of testing oneself.Phase inverter I6 receives between Sheffer stroke gate 114 and the waveform of testing oneself counting and the holding circuit 150.Circuit 150 is connected on I6 and tests oneself between the waveform relay drive 152.The waveform of testing oneself counting and holding circuit 150 were counted the umber of pulse of the waveshape detector output 132 of testing oneself in a transmission cycle.When the pulse number of being counted surpassed a set-point (such as 3), circuit 150 sent an output signal 154 to the waveform relay drive 152 of testing oneself.The waveform relay drive 152 of testing oneself produces the waveform output 82 of testing oneself, and it is illustrated in the waveform time gate window 116 of testing oneself whether have the waveform 102 of testing oneself.The waveform of testing oneself counting and holding circuit 150 comprise the input 156 that resets, and it is from transmitter 30.Circuit 150 resets at the reset pulse that the beginning in every transmission cycle is sent out device 30.
Whether there is the expression of liquid in the gap 20 that main waveform output signal 80 is detectors 10.When the liquid that time gate ultrasonic detector of the present invention can be used in the detection receptacle reaches specified level.Detector 10 is contained in this specified level, and when liquid rises and enters gap 20, ultrasonic signal passes the speed of propagating in the gap just to be increased, and like this, in main waveform time gate window 120, receiving transducer 16 just can detect the arrival of main waveform.Main waveform output signal 80 will be indicated in the gap 20 liquid.
The used time is relevant with the density of this material because ultrasonic signal passes certain material propagation, so this time gate design proposal can be measured the density and the interface location of material simultaneously.The measurement of density of material is the signal speed when passing this material, reflects density of material with the measurement transmission time.Usually, when density measurement, control main wave-shape amplitude with automatic gain control (AGC).When knowing the density of two kinds of materials, this spy device can be surveyed the interface of two kinds of storerooms in the gap according to the variation of signal speed.
Self-test output 82 is the intact expressions of detector 10.If detector 10 works, should send pulse and exist all the time along with each by detector sway brace 18 from detecting waveform.This just has many advantages.Even rapidoprint is arranged in the gap also can continuous self test to be surveyed and not to increase parasitic crystal with each transducer of independent test.Therefore the overall dimensions of detector 10 can reduce with scalable various application.
Especially, the repertoire of this structure detection detector, but not single detector.This detector body is constructed to strengthen the integrality of machinery with thick sway brace.In arm, there is no need to resemble prior art vibration type detector restricting signal intensity.If the transmission of the signal by sway brace has high amplitude and will improve but not diminish performance.
The sensing testing point can more thickly be placed in the multiple spot detector together because do not have crosstalking between each detector here, and the ultrasonic signal amplitude is reduced to insignificant level in about 1 millisecond.Because every bit needs less line, a large amount of check points allow, and sway brace can be made into physical strength high.Need less line to be because no longer need from detecting parasitic crystal.
Identical performance can only be finished with a transducer.In this embodiment, tested ultrasonic signal is that the surface of the other end from the gap from transducer is reflected back toward.For example, Fig. 7 is the sectional view of the single transducing detector of the present invention.Detector 160 comprises body 162, bridge 164, and reverberator 166, transducer 168 and gap 170 are to reverberator 166 emission incident waves 172.The reflection wave 174 that returns from reverberator 166 passes gap 170 to transducer 168.Reverberator 166 is made the surface energy that makes its adjacent gap 170 crystal 168 is returned in reflection wave 174 focusing.In the embodiment shown in fig. 7, this surface is to have the concave surface that correct curvature is made with a kind of machinery that reflection wave 174 is focused on crystal 168.But reverberator 166 can be general plane.
Embodiment shown in Figure 2 also can do to such an extent that have only single transmitter, and it sends and receive ultrasound wave.In this implementation, main waveform 48 is 46 propagation from transducer 40 along internal diameter, and from wall 43 reflected back transducers 40.The waveform 50 of testing oneself is propagated around and is returned transducer 40 along the wall 43 of pipe or container 44.
Time gate configuration of the present invention also is used for having the ground of discriminating to receive main waveform from the noise waveform that detector sway brace (perhaps supporting arm) produces.If the signal that the detector supporting arm produces is not to be used for self-test function, then the signal in the supporting arm is exactly a noise waveform.This noise waveform is commonly considered as sending crosstalking between transducer and receiving transducer.When the amplitude of noise waveform during much smaller than the amplitude of main wave table, main waveform enabling signal only can make carries out main wave test between main waveform time gate window phase.This provides quite wide tolerance limit, so that curb noise waveform by regulating main waveform threshold voltage.So noise waveform is not disturbed main waveform.
Time gate ultrasonic detector of the present invention is used in any application scenario of measuring physical characteristics of materials in the given spacing in fact.Although the present invention illustrates that with reference to listed embodiment the personnel that are familiar with this respect can find and can make the change on formal or the details and not deviate from the spirit and scope of the present invention it.Such as, the microprocessor of the more available delimitation time gate window between amplifier output 88 (Fig. 4) and threshold voltage is realized.Computer-controlled software program also can carry out this comparison.Digital signal processor (DSP) integrated circuit also can be in order to circuit shown in substituting.Too big so that cause when disturbing when the signal amplitude of testing oneself at main time window, can do supporting arm discontinuously to strengthen its attenuation.This uncontinuity can on supporting arm, do some around rib, with circular whorl, these lines can be rectangle, del or leg-of-mutton.These ribs are as resonant element and absorb the signal of propagating along supporting arm.Discontinuous density is 1/4 wavelength and leave this supporting arm renewed treaty half wavelength at interval preferably.To same supporting arm, different sizes can be with different ribs so that a topped wavelength period.Supporting arm not necessarily will place one side of detector, also can place on the central shaft of detector.
Claims (19)
1. detection method with automatic self-test function, be used for surveying to whether there being material to exist in the fixed gap by ultrasonic detector, sonac has the transducer apparatus of linking to each other for the bracket institution of fixed gap with common vicinity, and provide pulse in to fixed gap, to produce ultrasonic signal to transducer apparatus, it is characterized in that this method comprises:
Response adds pulse to described transducer apparatus and in each measuring period, provides many signals to make main time window and the time window of testing oneself, and they are separated in time according to the pulse of transducer apparatus;
Described signal pass along first path form main waveform to fixed gap with along second, after the different paths of testing oneself forms the waveform of testing oneself, receive described ultrasonic signal in each measuring period by described transducer apparatus;
Provide main waveform threshold level and the waveform threshold level of testing oneself;
With the amplitude and the main waveform threshold level of the ultrasonic signal received each measuring period and the waveform threshold level of testing oneself relatively, produce and represent these masters relatively relatively to export and test oneself and relatively export;
Produce representative is being given has material to exist in the fixed gap main waveform output in the existence of definite main waveform that integration master during the main time window relatively exports and the function that in main time window, exists as main waveform; And
Integration is tested oneself relatively to export with the waveform of determining to test oneself and is existed during the time window of testing oneself, and if the waveform of in the time window of testing oneself, testing oneself exist, produce and represent this methodological function waveform of testing oneself normally to export.
2. method as claimed in claim 1, it is characterized in that providing the step of ultrasonic detector to be included as transducing head provides and sends transducer and receiving transducer, and they are by separating to fixed gap and being linked to each other by supporting construction.
3. method as claimed in claim 1 is characterized in that providing the step of ultrasonic detector to comprise:
The transducer that sends and receive ultrasonic signal is provided for transducing head; And
Have one across the ultrasonic reflection surface that faces to fixed gap and this transducer for supporting construction provides, turn back to this transducer again so that ultrasonic signal is issued to this reflecting surface from this transducer.
4. method as claimed in claim 1 is characterized in that:
The ultrasonic signal that receives is added to a main waveshape detector;
Provide the step of many signals to comprise, allowing signal with a main waveform is to produce its main time window, first giving selecting in the time period and should main waveform allow signal effective and it keeps effective status during main time window after adding driving pulse to transducing head; And
This method also comprises and allows this main waveform signal to be added to this main waveshape detector so that start the step that the ultrasonic signal amplitude that is received is compared with main waveform threshold level during its main waveform time window.
5. method as claimed in claim 4 is characterized in that providing the step of many signals also to comprise:
Send inhibit signal with one and produce main time window, adding driving pulse after, second give that to select this transmission inhibit signal in the period to keep the invalid initialization pulse waveform that produced with the prevention transducing head before main waveform detected to transducing head; And
This transmission inhibit signal is added to main waveshape detector so that the step that No starting is compared the ultrasonic signal amplitude that is received with main waveform threshold level when this transmission inhibit signal is invalid.
6. method as claimed in claim 4 is characterized in that also comprising:
When main waveform allows signal effective, and during main time window, main relatively output is added to a main integral of pulse shape device; And
When its main waveform allows invalidating signal and outside main time window, stop comparison output signal to arrive integrator.
7. the method for claim 6 is characterized in that producing also being included in the step of main relatively output when the ultrasonic signal that is received surpasses main threshold level and produces a series of pulses, and the step that the integration master relatively exports comprises:
In main time window, the pulse number in the main relatively output is counted; And
Function as the pulse number of being counted produces the main waveform output that sign has main waveform to exist.
8. the ultrasonic detector of fixed gap internal memory at liquid given in a measurement, and this detector comprises: a supporting construction; With the transmission signal source, be used for sending signal in each generation measuring period;
It is characterized in that this detector also comprises:
Transducer apparatus links to each other with transmiting signal source with bracing or strutting arrangement, and transducer apparatus is positioned near the gap, is used for response and sends signal and launch ultrasonic signal in each measuring period, if a) through the gap and liquid is arranged, by liquid, determine main waveform in the gap; B) determine the ripple of testing oneself by supporting construction, and be used at signal by the gap with by receive the ultrasonic signal of transmission after the supporting construction in each measuring period;
The time gate generating means, with send signal source and link to each other, be used to receive described transmission signal and reach with respect to the transmission signal that receives and the velocity of sound by liquid, determine main time window, in to the transmission signal that receives and the velocity of sound by supporting construction, determine the time window of testing oneself;
Main waveform threshold generator is used to produce main waveform threshold level;
Main waveform comparator, link to each other with main waveform threshold generator, be used for to receive ultrasonic signal amplitude and main waveform threshold level relatively, and produce main relatively output, have and receiving the main waveform pulse of ultrasonic signal amplitude when surpassing main waveform threshold level at every turn;
Main waveform counter, be used for during main time window, counting the main pulse number that is provided, and generation output, function as counting main pulse number, during being characterized in main time window whether main waveform is arranged, main waveform counter comprises the RESET input, links to each other with the transmission signal source, is used for the main waveform pulse number that resets when transmitting and be counted receiving;
The threshold generator of testing oneself produces the waveform threshold level of testing oneself;
The comparer of testing oneself, threshold generator links to each other with testing oneself, be used for the ultrasonic signal amplitude that will receive and test oneself the waveform threshold level relatively, and produce the relatively output of testing oneself, have receiving the ultrasonic signal amplitude at every turn and surpass the pulse of testing oneself when testing oneself the waveform threshold level; And
The counter of testing oneself, be used for during the time window of testing oneself, counting the pulse of testing oneself that is provided, and produce the output of testing oneself, function as the pulse number of testing oneself that is counted, be characterized in the waveform of whether testing oneself during the time window of testing oneself, the counter of testing oneself comprises the RESET input of testing oneself, and is used for the pulse number of testing oneself that resets and be counted when receiving the transmission signal.
9. ultrasonic detector as claimed in claim 8 is characterized in that transducing head comprises transmission transducer and the receiving transducer that is separated by the gap.
10. ultrasonic detector as claimed in claim 9 is characterized in that supporting construction is included in the bridge that sends between transducer and the receiving transducer.
11. the ultrasonic detector of claim 9, it is characterized in that supporting construction comprises the container with annular wall, its internal diameter constitutes described gap, transducing head link to each other with chamber wall make ultrasonic signal from send transducer by the gap first path and be sent to receiving transducer along second path of toroidal container wall.
12. ultrasonic detector as claimed in claim 8 is characterized in that transducing head comprises not only to send but also the transducer of received ultrasonic signal.
13. as the ultrasonic detector of claim 12, it is characterized in that supporting construction comprise one across gap and transducer over against the ultrasonic reflection face, pass the gap from transducer through the ultrasonic signal of first propagated and arrive this reflecting surface and return this transducer again.
14. ultrasonic detector as claimed in claim 8 is characterized in that: send signal source and comprise:
With the oscillator that transducing head and time gate generating means link to each other, be used for periodically producing the transmission signal.
15., it is characterized in that also comprising as the ultrasonic detector of claim 14:
Be connected on oscillator and main waveform counter and the reset circuit between the counter of testing oneself, when receiving that each sends signal counter reset.
16. ultrasonic detector as claimed in claim 8, it is characterized in that the time gate generating means is suitable for producing usually invalid main waveform and allows signal, this signal becomes after the first preselected time section of receiving after transmitting signal effectively, and during main time window, keep effectively, wherein main waveform allows signal startup effectively the time to be used for the device that the gating master relatively exports, when invalid, then forbid this strobe unit, the device that described gating master relatively exports is gone up the main waveform pulse that each pulse that produces provides gating to main relatively output during being formed in main time window, and is stopping each pulse that produces in the main relatively output outside the main waveform time window.
17. the ultrasonic detector of claim 16 is characterized in that the time gate generating means comprises first RC network, it produces its main waveform according to a RC time constant and allows signal.
18. ultrasonic detector as claimed in claim 8, it is characterized in that the time gate generating means is suitable for producing the invalid permission signal of testing oneself usually, this signal becomes after second time period of receiving after transmitting signal effectively, and during the time window of testing oneself, keep effectively, wherein test oneself and allow signal startup effectively the time to be used for the device that gating is tested oneself and relatively exported, when invalid, then forbid this strobe unit, described gating is tested oneself relatively and during the device of output is formed in the time window of testing oneself the pulse of testing oneself that each pulse of testing oneself that produces provides gating is gone up in the relatively output of testing oneself, and is stopping each pulse that produces in the relatively output of testing oneself outside the time window of testing oneself.
19. as the ultrasonic detector of claim 18, its time gate generating means comprises second RC network that produces the permission signal of testing oneself according to the 2nd RC time constant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US73718091A | 1991-07-29 | 1991-07-29 | |
| US07/737,180 | 1991-07-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1069123A CN1069123A (en) | 1993-02-17 |
| CN1045658C true CN1045658C (en) | 1999-10-13 |
Family
ID=24962893
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN91112613A Expired - Fee Related CN1045658C (en) | 1991-07-29 | 1991-12-30 | Time gate ultrasonic sensor and method |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0596966A4 (en) |
| JP (1) | JPH07501138A (en) |
| CN (1) | CN1045658C (en) |
| AU (1) | AU2373192A (en) |
| WO (1) | WO1993003340A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4163629A4 (en) * | 2020-06-08 | 2024-05-22 | Toshiba Kk | Processing device, processing system, processing method, program, and storage medium |
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| US5428984A (en) * | 1993-08-30 | 1995-07-04 | Kay-Ray/Sensall, Inc. | Self test apparatus for ultrasonic sensor |
| US5452611A (en) * | 1993-12-09 | 1995-09-26 | Kay-Ray/Sensall, Inc. | Ultrasonic level instrument with dual frequency operation |
| US5735166A (en) * | 1994-12-12 | 1998-04-07 | Cosense, Inc. | Ultrasonic micro-sensor for level leak alert and interface detector |
| FI97829C (en) * | 1995-06-07 | 1997-02-25 | Acutest Oy | Measurement method and equipment for determining interfaces |
| JP2001272266A (en) * | 2000-03-27 | 2001-10-05 | Ricoh Elemex Corp | Ultrasonic level gauge |
| BR112015019967A2 (en) * | 2013-03-18 | 2017-07-18 | Skf Ab | sensor self test |
| CN104931580A (en) * | 2015-06-01 | 2015-09-23 | 北京哈特凯尔医疗科技有限公司 | Detecting system of air in liquid media |
| CN105137436B (en) * | 2015-08-31 | 2019-01-04 | 湖南汇博电子科技股份有限公司 | Passageway for fire apparatus checks system and method |
| CN105157790A (en) * | 2015-10-26 | 2015-12-16 | 天津商业大学 | Aided non-full-pipe detection device for electromagnetic flowmeter |
| CN107561157B (en) * | 2016-06-30 | 2023-08-04 | 重庆医科大学 | Water quality detector and method thereof |
| CN106768185A (en) * | 2016-12-14 | 2017-05-31 | 金陵科技学院 | Oil tank Interface detection device and method based on ultrasonic velocity and liquid medium resistance |
| EP3486619A1 (en) * | 2017-11-17 | 2019-05-22 | Hochschule für angewandte Wissenschaften Fachhochschule Coburg | Device and method for detecting deposition layers in a conduit conducting a liquid or a soft medium and/or for level detection |
| CN112985545A (en) * | 2019-12-17 | 2021-06-18 | 西安定华电子股份有限公司 | External liquid level measuring switch and external liquid level measuring method |
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| US4482889A (en) * | 1980-11-14 | 1984-11-13 | Nippondenso Co., Ltd. | Device for detecting failure of ultrasonic apparatus |
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- 1991-12-30 CN CN91112613A patent/CN1045658C/en not_active Expired - Fee Related
-
1992
- 1992-07-16 EP EP19920916332 patent/EP0596966A4/en not_active Withdrawn
- 1992-07-16 WO PCT/US1992/005892 patent/WO1993003340A1/en not_active Application Discontinuation
- 1992-07-16 AU AU23731/92A patent/AU2373192A/en not_active Abandoned
- 1992-07-16 JP JP5503583A patent/JPH07501138A/en active Pending
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| US4630245A (en) * | 1983-07-15 | 1986-12-16 | Introtek Corporation | Non-contacting liquid level detection system |
| US4909080A (en) * | 1987-10-31 | 1990-03-20 | Toyoda Gosei Co., Ltd. | Ultrasonic level gauge |
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| EP4163629A4 (en) * | 2020-06-08 | 2024-05-22 | Toshiba Kk | Processing device, processing system, processing method, program, and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0596966A1 (en) | 1994-05-18 |
| WO1993003340A1 (en) | 1993-02-18 |
| JPH07501138A (en) | 1995-02-02 |
| AU2373192A (en) | 1993-03-02 |
| CN1069123A (en) | 1993-02-17 |
| EP0596966A4 (en) | 1994-09-21 |
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