SU679815A1 - Ultrasonic speed metering device - 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 areas of the industry.

A device for measuring the speed of ultrasound is known, which contains acoustic transducers, a source of reference time intervals for comparing measured time with a reference one, and a tracking unit that automatically changes the reference time according to measured 1, 2.

These devices only allow measurements in a pulsed mode at a fixed frequency and do not provide sufficient measurement accuracy.

The closest in technical essence to the invention is a device including radiating and receiving electroacoustic transducers, a quantized delay line, an input amplifier, an output amplifier-driver, a matching circuit and an adjustable delay line 3.

A disadvantage of the known device is the impossibility of measurements in a wide frequency range and low measurement accuracy caused by the instability of the adjustable delay line.

The aim of the invention is to expand the operating frequency range and improve the measurement accuracy.

The undelivered Pel is achieved by the fact that the excitation generator, the output of which is connected to the radiating transducer, the first polar null-organ, is connected to the device for measuring the speed of ultrasound, including the emitting and receiving electroacoustic transducers, the quantized delay line between the receiving transform gel and one of the inputs of the coincidence circuit, and the second polar null organ connected between the output of the excitation generator and the input quantized The delay line, while reg.L1; the delay line is designed as a controllable quantized delay line, the input of which is connected to the output of the quantized delay delay, the output to the second input of the coincidence circuit, and the control input to the output of the coincidence circuit.

FIG. 1 shows a block diagram of the device, FIG. 2 is a block diagram of a controlled quantized delay line; FIG. 3 - stress plots for the work of the device.

The device contains an excitation generator 1, designed to excite oscillations of a given shape and duration, electroacoustic radiating 2 and receiving 3 non-converters, which serve to convert electrical energy into mechanical oscillation energy and vice versa, to the cell with the test medium 4, and the first nullar organ 5, which forms a short emulsion with a steep non-rare front at the occurrence of a positive signal through zero, a coincidence circuit 6, the second polar null-organ 7, a quantized delay line 8 serving to select and the measurement range, the quantized controllable delay line 9 adapted to further delay nmnulsov.

In one of the possible embodiments, the block diagram of the controlled quantized delay line contains: a trigger with separate inputs 10, an AND generator, in return of which a thermally stabilized delay line (L31) 12 is turned on, an oscillator 13 that controls the frequency of the oscillator 11, the generator linearly varying voltage 14, generating a bias voltage, a starting generator 15, used to start the generator of a linearly varying voltage, and a frequency divider 16, dividing the frequency of the generator 11.

The device works as follows. The generator 1 generates periodic electric oscillations of a given shape, which, when it is not available to the transmitting transducer 2, are converted into acoustic oscillations and, having passed through the cuvette with the test medium 4, are fed to the receiving transducer 3. -organ 5, which forms short impulses with a steep non-intermediate front, arriving at the first input of the joint scheme 6. At the same time, the signal from the generator 1 nostunat to the input of the second polar well organ 7, the pulses from the output of which are delayed by the quantized line of the delay: ki 8, for a time (TI is the signal transit time in the medium under study). From the output of the quantized delay line 8, the pulses arrive at the input of the controlled quantized delay line 9, at the output of which pulses are received that are delayed by time T2 + T3. These pulses arrive at the second input of the coincidence circuit 6, the signal at the output of which becomes equal to zero when T2 + Tz becomes equal to Tb

FIG. 3 shows signal plots at the outputs of the device blocks, where o is the signal at the output of the excitation generator 1, b is the signal at the output of the receiving transducer 4, e is the signal at the output of the zero organ 5, g is the signal at the output of the zero organ 1, d the signal at the output of the quantized delay line 8, e is the signal at the output of the controlled quantized delay line 9, l is the signal at the output of the generator of linearly varying voltage, h is the signal at the output of the matching circuit 6, w is the signal at the output of the starting generator 15, K - combination of pulses at the circuit input

coincidence 6.

The controllable quantized delay line works as follows: when a pulse arrives at the trigger input 10 from the output of the quantized delay line 8,

it tilts to state (1) and starts the generator AND, in the feedback of which LZT is turned on 12. The delay time of the LZT is changed by the magnetic field of the puller 13. From generator 11, the pulses arrive at the input of frequency divider 16. After the arrival of the lth imiuls, where n is the division factor, at the output of the divider, an imiuls is generated that arrives at the second input of the trigger 10. The trigger is tilted to the state (0), and the circuit returns to the initial position. The start-up generator 15 and the error signal from the output of the coincidence circuit 6 start the generator of linearly varying voltage

And, which, with the aid of the magnetic field of the magnetic field coil 13, controls the frequency of the oscillator 11, the delay time is fine. The quantized delay line 8 is made similarly to the delay line 9 with the exception of the control circuit, and the delay time in it, fj, is changed discretely by the choice of the division factor. Thus, knowing the division factor of the delay line 8 and the voltage of the generator 14 at the moment of assembly, it is possible to determine the delay time of the ultrasonic signal in the sample ti Ha + T3.

The invention provides the ability to conduct measurements at any frequency.

both in the pulsed and in the continuous modes, as well as the increase in the measurement accuracy by using a more stable controlled quantized delay line.

Claims (3)

1. USSR Author's Certificate No. 304448, cl. G 01H 5/00, 1971. 2. Perepechko I. I. Acoustic research of polymers. Publishing house "Him, M., 1973. 3. USSR author's certificate number 441456, cl. G 01H 5/00, 1975 (prototype).