SU879439A1 - Method and device for measuring ultrasound speed - Google Patents

Description

54) METHOD FOR MEASURING THE ULTRASOUND SPEED AND DEVICE FOR ITS IMPLEMENTATION

one

The invention relates to non-destructive testing by an ultrasonic method and can be used to measure the velocity of ultrasound for analyzing the composition of gas mixtures.

A pulse frequency method for indirect measurement of the speed of ultrasound and its corresponding device are known, based on the measurement of the frequency ratio of the auto-circulation of electro-acoustic pulses in the measuring and reference channels.

The disadvantage of the known method and device is that with accurate measurements there is a relative measurement error due to the delay of the impulse BI of the protective membranes, sound ducts and electronic circuit.

The method of measuring the speed of ultrasound is the closest to this invention in its technical essence and the achieved result. It consists in that ultrasound pulses are excited by ultrasound pulses passed through the medium in the controlled and reference environment and emit an electrical impulse that again excites

The emitter, with the help of an additional receiver, provides unidirectional passage of the ultrasonic pulse from the emitter to the main receiver, forms rectangular pulses in the controlled and reference channels with a frequency of its channel and a duration equal to the time from the additional to the main receiver, respectively, in the controlled and the reference media, fill the specified rectangular pulses with high-frequency pulses of a stable frequency and calculate The number of electric pulses of the controlled channel during the time interval during which the number of high-frequency pulses 20 that fill the rectangular pulses of this channel will reach a predetermined number, and the ultrasound speed is judged by the frequency of the intervals in the calibrated time interval, and also the device for implementation of this method, containing, respectively, in a controlled and reference channels, series-connected pulse generator and emitter, main receiver, main amplifier The matching unit, the output of which is connected to the input of the pulse generator, the converter designed for positioning, respectively, in controlled and reference environments on the way, the spread of the ultrasonic and pulse between the radiator and the main receiver and the electrical output connected to the additional amplifier and forming unit, trigger, The first input of which is connected to the output of the additional amplifier-forming unit and the second input - to the output of the main amplifier-forming unit, sequentially connected the first high-frequency pulse generator, the first stage of the coincidence, a frequency divider, the second stage of matches and reversible pulse counter, and Auto swarm trigger input in the test channel is connected to the second input of the second-stage matches, the output - to the second input of the first coincidence cascade. A disadvantage of the known technical solutions is that when they are used for indirect measurements of the velocity of ultrasound, the measurement accuracy is low. The aim of the invention is to increase the measurement accuracy. This goal is achieved by the fact that at the end of the counting of the number of electric pulses of the monitored channel, the same electric pulses of the reference channel are counted, and the ultrasound speed is given by the total number of high-frequency pulses that fill the rectangular pulses of the reference channel. The proposed method implements a device equipped with the third and fourth coincidence cascades, the second high-frequency pulse generator and the second pulse counter, the first pulse counter is made random, its summing input is connected to the output of the second coincidence cascade, the subtracting input is with the output of the third coincidence cascade , and the output is connected with the first inputs of the third and fourth stages of coincidence, the second input of the third stage matches with the output of the frequency splitter, with the second input of the fourth stage with n and the reset input of the second pulse counter, the counting input of which is connected to the output of the fourth cascade of coincidences, the third input of the fourth cascade of coincidences is connected to the output of the trigger of the reference channel, the fourth in the course of the fourth cad coincidence is connected to the output of the second generator of high-frequency pulses, and the third input of the third coincidence stage is connected to the output of the main amplifying-forming unit of the reference channel. The drawing shows the block diagram of the device for implementing the method. A device for carrying out the method comprises, respectively, in a controlled and reference channels a series-connected 1-pulse generator and emitter 2, the main receiver 3, the main amplifier-forming unit 4, the output of which is connected to the input of the pulse generator 1, a converter 5 designed to be located in the controlled and reference, respectively environments on the path of the ultrasonic pulse between the emitter 2 and the main receiver 3 and the attached electrical output to additionally mu amplifying block 6, the trigger 7, the first input of which is connected to the output of the additional amplifying block b, and the second input - to the output of the main amplifying block 4, connected in series the first generator 8 high-frequency pulses, the first stage 9 coincidence divider 10 frequency, the second cascade 11 Denpa and reversible counter 12 pulses, and the second, trigger 7 in the controlled channel is connected to the second input of the second cascade 11 matches, the output - with the second input of the first cascade 9 y. The device is equipped with the third and fourth cascade 13,14 coincidences, the second generator 15 high-frequency pulses and the second counter 16 pulses, the first counter 12 pulses are reversible, its summing input is connected to the output of the second cascade 11 matches, subtracting the input from the output of the third cascade 13 matches, and the output is connected to the first inputs of the third and fourth cascades 13,14 matches, the second input of the third stage 13 matches is connected to the output of the frequency divider 10, with the second input of the fourth stage 1.4 matches and About the reset input of the second counter 16 pulses, the counting input of which is connected to the output of the fourth cascade 14 matches, the third input of the fourth cascade 14 matches connected to the output of the trigger 7 of the reference cascade, the fourth input of the fourth cascade 14 coincidences connected to the output of the second generator 15 high-frequency pulses, and the third the input of the third cascade 13 matches connected to the output of the main amplifier-forming unit 4 of the reference channel. The device works as follows. . In a controlled channel, the generator 1 generates an electrical impulse to the radiator 2, which converts it into an acoustic impulse. The acoustic impulse, after passing through the controlled medium, is partially accepted by converter 5, partially reflected from its plane and received by receiver 3, converted into electrical, passes the main amplifying-forming unit 4, is fed to the second inputs of trigger 7 and cascade 11 coincidences, as well as to input of generator 1 , causing a repeated cycle of generation and propagation of electroacoustic pulses along the synchro-ring formed by block 4, generator 1, radiator 2, receiver 3 and converter 5. An acoustic pulse is received The transducer 5 is converted into an electrical one, passes through an additional amplifier-forming unit b, and is fed to the first input of trigger 7. An electrical impulse from the output of trigger 7 is equal in duration to the sum of the parasitic delay time and the acoustic pulse in the emitter 2 to Converter 5, is fed to the second input of the stage 9, than interrupts the passage of pulses from the output of the generator 8 through the cascade 9 to the input of the divider 10. Electric pulses from the output of the dividers 10, increased in duration NOSTA directly proportsiolalno lobe spurious time DELAY ski and transit time of the acoustic pulse in the medium from the radiator 2 to the converter 5 are input to the first input of the coincidence stage 11 and is controlled by the passage of pulses from the output unit 4 to a summing input of the counter 12.

In the reference channel, the generator 1 generates an electrical impulse arriving at the radiator 2, which converts it into an acoustic impulse. The acoustic impulse, having passed the reference medium, is partially accepted by converter 5, partially reflected from its plane and received by receiver 3, passes through the main amplifier-forming unit 4, enters the second input of trigger 7, as well as the input of generator 1, causing a repeated generation cycle and propagation of electroacoustic pulses along the synchro-ring formed by block 4, generator 1, emitter 2, receiver 3 and transducer 5. An acoustic pulse received by transducer 5 is converted into electric, An additional amplifier-forming block b passes and goes to the first input of the trigger 7.

At the time of the prohibition signal from the output of the divider 10 to the first input of the cascade 11, the passage of pulses from the output of block 4 to the summing input of the counter 12, in

where a number proportional to the ultrasound speed in the monitored channel is recorded, at the same time point, from the second output of the divider 10, the enabling signal is fed to the second inputs of the cascades 13, 14 of the matches. The leading edge of the resolving signal from the output of the divider 10 simultaneously enters the reset input of the counter 16, which causes its bits to be reset. Insofar as

o at the first inputs of the cascades 13 14 there is a resolving potential from the output of the counter 12, then the flow of pulses from the output of the block 4 through the cascade 13 to the

5 subtracting the input of the counter 12, as well as pulses from the output of the generator 15 through a cascade 14 to the input of the counter 16.

The arrival of pulses from the output of the generator 15 through the cascade 14 to the input of the counter 16 is interrupted by -; pulses

0 coming from the output of the trigger 7 to the third input of the cascade 14 and equal in duration to the sum of the propagation time of the acoustic pulse in the reference channel from the radiator 2 to

5 converter 5 and the parasitic delay time of the reference channel.

At the moment of zeroing the bits of the counter 12, a prohibiting signal is fed to the first inputs of the stages 13 and 14, than

0, the flow of pulses from the output of block 4 through cascade 13 to the subtractive input of counter 12, as well as pulses from the output of generator 15 through to C 1 and 14 to the input of counter 16, stops,

5 on the indicators of which a number is displayed that is equal to the ratio of the speeds of ultrasound propagation in the controlled and reference channel. AND:. The indication of the measurement result continues until the appearance of the permissive. the signal from the output of the divider 10 at the input of the cascade 11, and therefore prohibiting signal from the output of the divider 10 at the second inputs of the cascades 13 and 14, since

5, the leading edge of the prohibiting signal, when appearing at the input of the counter 16, is not capable of resetting it.

At the moment of the appearance of the second inhibitory signal from the output of the divider 10

0 at the input of the cascade 11, the measurement process is repeated.

The number of Ny pulses received at the summing input of the counter 12,

m -fr

PLWNG)

.T;

WITH

five

k is a constant coefficient

Where

t distribution time

. tic signal between the transducer 5 and the receiver 3 in the controlled channel;

C | - the speed of ultrasound in a controlled channel;

K is the frequency division factor of the divider 10.

five

Upon receipt of pulses from the output of block 4 through a cascade 13 to the subtracting input of counter 12 with a period T equal to

T - TVTVA, C 2

-g

the propagation time of the acoustic pulse between the transducer 5 and the receiver 3 in the reference channel

By propagating the acoustic pulse between emitter 2 and transducer 5 in the reference channel, the parasitic delay time (in

d electronic circuit, membranes and sound ducts) in the reference channel, a time interval T is formed, equal to:

(t% td). (h;

The interval T of the time during which the pulses from the output of the generator 15 will not pass to the input of the counter 16 through the cascade 14 will be

T2 m (t + l),. (T + l). (l;

For the measurement interval Ti time the record is valid

(.,with.)

c-)

KS (T4L) KS, T

For the interval T. to the input of the counter 16, through the cascade 14 from the output of the generator 15, pass t the number of fsjL pulses with a period TO equal to

Ik. Jibsl

(s)

t.

TB

Taking into account the expression (1) and the possibility of stabilizing values

N //, we have

. t ,, and to dl

N-.Holl

WITH

X T „T. with g

where K is a constant coefficient; C - the speed of ultrasound in

 reference channel. Thus, the result of indirect measurements of the velocity of propagation of ultrasonic vibrations by the described method and device is practically independent of the parasitic delay times of the channels and the time of the signal propagation between the transmitter and the transmitter, i.e. in the zone of unsteady propagation mode of acoustic pulses, that noSfciUtiaeT is the accuracy of ultrasound velocity measurements, npi is an appropriate choice of T and T values — the measurement error is several orders of magnitude smaller than when using the known synchro-ring methods and devices for indirect velocity measurement of ultrasound.

Claims (2)

1. The method of measuring the speed of ultrasound, consisting in that, in a controlled and reference environment, the ultrasound pulses are excited by the emitter, the ultrasonic pulses that pass through the medium are received by the main receiver, they form an electrical pulse, which the exciter again excites, by means of an additional receiver, the unidirectional passage of the ultrasonic pulse from the radiator to the main receiver is ensured; the reference channels are rectangular pulses with a frequency of its channel and a duration equal to the time of ultrasound With a standard pulse from the additional to the main receiver, respectively, in controlled and reference environments, the specified rectangular pulses are filled with high-frequency pulses of a stable frequency and the number of electrical pulses of the controlled channel is counted over a time interval during which the number of high-frequency pulses filling the rectangular pulses of this channel will reach a predetermined number, and the ultrasound velocity is judged by the frequency of the pulse intervals in the calibrated interval in This is different from the fact that, in order to increase the measurement accuracy after counting the number of electric pulses of the monitored channel, the same electric pulses of the reference channel are counted, and ultrasound speeds are judged by the total number of high-frequency pulses filling the rectangular pulses of the reference channel. . 2, a device for measuring the speed of ultrasound, containing, respectively, in a controlled and reference channels serially connected pulse generator and emitter main receiver main amplifier-forming unit, the output of which is connected to the input of the pulse generator, transducer, designed to be placed in controlled and reference media on the way, respectively propagation of the ultrasonic pulse to the membrane by the radiator and the main receiver and connected by an electrical output Trigger, the first input of which is connected to the output of the additional amplifying block, and the second input - to the output of an axial amplifying block, connected in series first generarator of high-frequency pulses, first stage of coincidence, frequency divider, second a cascade of coincidences and a reversible pulse counter, and the second input of the trigger in the controlled channel is connected to the second input of the second cascade of coincidences, the output to the second input of the first cascade drops, characterized by the fact that it is equipped with the third and fourth coincidence cascades, the second high-frequency pulse generator and the second pulse counter, the first pulse counter is reversible, its summing input is connected to the output of the second coincidence cascade, the subtracting input is with the output of the third coincidence cascade, and the output connected to the first inputs of the third and fourth cascade of coincidences, the second input of the third cascade of coincidence is connected to the output of the frequency divider, with the second input of the fourth cascade of coincidence and the reset input of the second pulse counter, the counting input of which is connected to the output of the fourth coincidence cascade, the third input of the fourth coincidence cascade is connected to the trigger output of the reference channel, the fourth input of the fourth coincidence cascade is connected to the output of the second high-frequency pulse generator, and the third input of the third coincidence cascade is connected with the output of the main amplifier-forming unit of the reference channel. Sources of information taken into account in the examination 5 1. Brazhnikov N.I. Ultrasound methods. M.-L., Energie, 1965, p. 133, 125-129. 2. USSR author's certificate 20 No. 679866, cl. G 01 N 29/00, 1977 (prototype.