SU441456A1 - Device for measuring the speed of ultrasound - Google Patents

Description

one

The invention relates to the field of measurement technology and can be used for various ultrasonic measurements in the chemical, oil refining and other industries.

A device for measuring the speed of ultrasound is known, comprising a generator connected through an input amplifier, ultrasonic transducers and an output amplifier with one input of a matching circuit, and through a delay unit and a terminal generator of selector pulses with another input of a matching circuit whose output is connected to a reversible motor.

However, such a device does not allow precision automatic measurements due to the low stability of the delay unit.

In the proposed device, a frequency divider between the generator and the delay unit, a time selection unit between the teperator and the input amplifier, a generator of selectable pulses between the frequency divider and the time selection unit, a terminal time selection unit connected to another input to the generator, and an adjustable electronic delay connected kinematically are entered with a reversible motor, between the terminal generator of selector pulses and another input of the assembly scheme, the gate generator between the output of the time block with the third entry of the joint scheme and the other entry of an electronic adjustable delay.

Due to this, it is possible to carry out precision automatic measurements of the velocity of ultrasound.

FIG. 1 shows a block diagram of the device; in fig. 2, ohm, - voltage plots, but the operation of the device.

The block diagram contains a source 1 of reference time intervals for comparing the measured time with the reference one, and a tracking unit 2 that automatically changes the reference time in accordance with the measured one. Source 1 includes a crystal oscillator 3, generating a non-periodic sequence of short rectangular PMs, a divider of 4 frequencies, performing frequency division of the generator 3, generator 5 of selector pulses, generating rectangular selectors, a time selection block 6 used to extract the necessary pulse from a sequence of pulses produced by the generator 3.

The amplifier 7 amplifies the power of the pulse generated by the block 6 temporary se. Acoustic receiving 8 and transmitting

9 converters serve to convert electrical energy into mechanical vibration energy and vice versa. The wideband output amplifier driver 10 performs an undistorted amplification of the electrical signal from the output of the acoustic receiving transducer 8 and the formation of this signal into a standardized amplitude and duration pulse.

The delay unit 11 is designed for the time delay of the pulses coming from the 4 frequency divider. The terminal generator 12 selector pulses, produces rectangular selectable pulses, and the time selection terminal unit 13 selects a pulse delayed by the delay unit 11. The strobe generator 14 generates a rectangular gating pulse (second half gate).

Adjustable electronic delay 15 serves to add additional delay to the pulses from the output of the 4 frequency divider, the value of which is automatically adjusted, as well as to generate a square pulse of the first half-strobe. The coincidence circuit 16 compares the time positions of the three pulses (the first and second half-gates and the pulse of the output amplifier 10) and the generation of the error signal. A reversing motor 17, kinematically coupled to a regulating element of the adjustable electronic delay 15, changes the amount of delay depending on the polarity of the error signal.

FIG. Figure 2 shows the voltage plots, where a is the pulses at the output of the quartz oscillator 3; b - pulses at the output of the divider 4 frequency; in - im-pulses at the output of the generator 5 selector pulses; g - pulses at the output of the block 6 time selection: 3 - pulses at the output of the block And the delay; e - pulses at the output of the terminal generator 12 selector pulses; W - pulses at the output of the terminal block 13 time selection; 3 - pulses at the output of the adjustable electronic delay 15; and - pulses at the output of the generator 14 (second half-strobe); K - pulses at the input of the output amplifier shaper 10; l - pulses at the output of the output amplifier-former 10; m - the combined image of the impulse l with the gating impulses s, i.

The device works as follows.

Generator 3 generates a periodic sequence of short rectangular pulses that arrive at frequency divider 4 and blocks 6 and 13. At the output of the frequency divider, there are rectangular pulses delayed by time relative to the main sequence of generator 3 by 3 - the delay time of the frequency divider. In order to obtain a non-delayed divided sequence of pulses from the output of the frequency divider, pulses are fed to the input of the generator 5 selector pulses, which produce wide rectangular pulses that arrive at the time selection unit 6. To the second input of this block, pulses are fed directly from the output of generator 3. Thus, at the output of block b, there is a 5 sequence of rectangular pulses, whose frequency is determined by the expression L

i, where / l

oscillator frequency 3; K - 1 division factor of the frequency divider.

The pulses from the output of block 6 are fed to the input power amplifier 7, and then to the transmitting transducer 9 of the acoustic sensor. Acoustic oscillations through the test medium reach the receiving transducer 8, where they are converted into electrical impulses (Fig. 2, k), and after amplification and formation by a wideband output amplifier shaper 10 arrive at

0 one input of circuit 16 matches.

At the same time, the pulses from the frequency divider are fed to the input of the delay unit 11, the delay time of which is determined by the measurement range. Delayed pulses trigger

5, the generator 12, its pulses arrive at block 13. The pulses of the main sequence from the generator 3 are fed to another input of block 13. At the output of block 13, a sequence of pulses is produced at a frequency i

0 is shifted in time relative to the sequence of pulses from the output of the frequency divider by the time T3. (Fig. 2, e). The pulses from the output of the block 13 are fed to the start of the adjustable electronic delay 15 and the generator

5 14 strobe (second half-gate).

An adjustable electronic delay produces a rectangular pulse, the duration of which Tza in total with the delay time Tz, is equal to the transit time of the acoustic pulse between converters 8 and 9. The rectangular pulse from the output of the adjustable electronic delay is supplied to another input of the matching circuit 16 and is the first pulse half the gate. Rear

5, the front of this pulse triggers the strobe generator 14 (the second half-gate), a square-wave pulse from the output of which is fed to the third input of the coincidence circuit 16. The generated

0 pulse from the output of the amplifier-amplifier 10 (the pulse is formed on the acoustic signal).

The combined image of the signal and two gating pulses is shown in FIG. 2 m

5 In position I, at the output of the coincidence circuit, a voltage of a certain polarity is generated, which powers the reversing motor 17. The latter moves the delay 15 until the error signal

0 at the output of the coincidence circuit 16 will not become zero (position III). In position II, at the output of the coincidence circuit 16, a voltage of opposite polarity is produced and the motor moves the delay 15 to the opposite side 5 to position III.

Thus, the proposed device allows, on the one hand, to carry out precision measurements, and on the other hand, to automate the measurement process, which, for example, with the increasing volume of dynamic testing of polymers, significantly increases labor productivity with high measurement accuracy.

Subject invention

An ultrasound velocity measuring device comprising a generator connected through an input amplifier, acoustic transducers and an output amplifier with one input of a matching circuit, and through a delay unit and a terminal generator of selector pulses with another input of a matching circuit, the output of which is connected to a reversible motor, that, in order to carry out precision automatic measurements of the ultrasound velocity, a frequency divider between the generator and the delay unit was inserted into it, the time selection block and between the generator and the input amplifier, gate pulse generator between the frequency divider and time selection unit, the end time selection unit,

connected by another input to the generator, and an adjustable electronic delay connected kinematically to a reversible motor, between the terminal generator of selector pulses and the other input of the coincidence circuit, the strobe generator between the output of the time selection unit, the third input of the coincidence circuit and the other input of the electronic adjustable delay.

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