SU679800A1 - Ultrasonic one-channel flowmeter - Google Patents

Description

one

The invention relates to the field of ultrasound measurements and can be used to measure the flow of liquids and gases in various fields of industry.

Known single-channel ultrasonic flow meters, including two electroacoustic transducers,. alternator, commutator and recording device operating by phase switching method {. Such devices, along with complexity, do not provide sufficient accuracy in measurements with rapid changes in the flow velocity.

The closest in technical essence to the proposed device is a single-channel ultrasonic flowmeter containing two electroacoustic transducers, two modulators, the outputs of which are connected to the corresponding electroacoustic converters, two selector amplifiers, the inputs of which are connected to the outputs of the modulators, a phase detector, the inputs of which are connected to the outputs of selector amplifiers, a switch, one of the outputs of which is connected to the control inputs of the modulators, and the second output is a control conductive enhancers selector inputs, and a generator, whose output is connected to the modulators 2. Raet phase sequence between received signals

in this device, it is directly proportional to the flow rate and is measured by a Phase detector.

The disadvantages of the known device are significant error

measurements and small dynamic range of flow measurements, due to the non-linearity of the static characteristics of the phase detector, due to non-linear distortion of signals

modulators, amplifiers and converters.

The aim of the invention is to increase the accuracy and increase the dynamic range of the flow measurement.

Claims (2)

This is achieved by introducing in series the frequency tuning unit, a controlled generator and a phase meter, the second input of the phase meter connected to the generator output, the output of the phase detector connected to the input of the frequency tuning unit, and the output of the controlled generator podkpk whose to the input of the second modulator. 36 The drawing shows the functional scheme of the proposed ultrasonic flow meter. The device contains modulators 1, 2 electroacoustic transducers 3, 4, selector amplifiers 5,6, phase detector 7, block 8 of frequency tuning, controlled oscillator 9, phase meter 10, oscillator 11, switch 12. The outputs of modulators 1 and 2 are connected with the corresponding electroacoustic converters 3 and 4 and with the input of selector amplifiers 5 and 6. The outputs of selector amplifiers 5 and 6 are connected to phase detector 7. Phase detector 7, frequency tuning unit 8, controlled oscillator 9, phase meter 10 are connected in series. The generator 11 is connected to the modulator 1 and to the phase meter 10. The first output of the switch 12 is connected to the control inputs of the modulators 1, 2, and the second output is connected to the control inputs of the selector amplifiers 5, 6. The module 2 is connected to the output of the controlled generator 9. The device operates as follows. Continuous high-frequency signals of the generator 11 and the controlled generator 9 are converted by modulators 1, 2 into bursts. The length and duration of these packets are constant and determined by the intrinsic parameters of the switch 12, the signals of which are sent to the modulators 1, 2. The pulses go to the electroacoustic transducers 3, 4 and are simultaneously radiated into the medium under study and upstream. At the moment of radiation, the selector amplifiers 5, 6 are closed by the output voltage of the switch 12. Ultrasonic signals passing through the stream are shifted along the Phase relative to each other by an amount proportional to the flow rate. Received pulses are converted by electroacoustic transducers 3, 4 into electrical pulses amplified by selector amplifiers 5, 6, which are opened for the time of reception by the voltage of switch 12, and fed to phase detector 7. The output voltage of phase detector 7 is fed to block 8 frequency tuning, which changes the frequency of the controlled oscillator 9 until the phase difference of the signals at the inputs of the phase detector 7 is compensated. at the time of compensation, its output voltage is equal to the difference The phases between the harmonic voltages of the generator 11 and the controlled generator 9, measured by the phase meter 10, correspond to the phase shift of the ultrasonic signals in the stream (i.e., The output voltage of the phase meter is 10 directly proportional to the measured flow. The accuracy of the proposed device is increased due to the fact that the fab detector 7 operates near the zero point of its operating characteristic, therefore the nonlinearity of its static characteristic does not reduce the accuracy of the flow measurement. In addition, the inputs of the phase meter 10 receive harmonic signals directly from the generators 9 and I, mine modulators 1, 2, electroacoustic transducers 3,4, selector amplifiers 5, b. Therefore, the linearity of the static characteristic of the phase meter 10 is significantly higher than that of the prototype phase detector. The presence of continuous useful signals at the outputs of generators 9 and 11 makes it possible to use as a phase meter 10 domestically produced digital meters of phase differences, the measurement range of which exceeds the measurement range of phase detectors, which increases the upper limit of the measured flow rates. Claims of the invention Single-channel ultrasonic flowmeter containing two electroacoustic transducers, two modulators, the output of which is connected to the corresponding electroacoustic transducers, two selector amplifiers, the inputs of which are connected to the outputs of the modulators. A phase detector, whose inputs are connected to the outputs of selector amplifiers, a switch, one of the outputs of which is connected to the control inputs of the modulators, and a second output to the control inputs of the selector amplifiers, and a generator, the output of which is connected to the input of one of the modulators, different By the fact that, in order to increase accuracy and increase the dynamic range of measurements /, serially connected frequency tuning / control generator and phase meter are inserted into it and the second phase meter input is connected to the output dy generator, the output of the phase detector is connected to the input of the frequency adjustment, and an output of the controllable oscillator is connected to the input of the second modulator. Sources of information taken into account in the examination 1..Brazhnikov I.I. Ultrasonic phase metering, M., Energie, 1968, p. 236. 2. USSR author's certificate 211813, cl. G 01 F 1/00, 1968 (prototype).