SU872965A1 - Single channel ultrasonic flowmeter - Google Patents

Description

The invention relates to instrumentation, and in particular to ultrasonic instrumentation, and can be used to measure the flow of liquids.

-Izvesten single channel ⁵ · kovoy Ultrasound flowmeter comprising an ultrasonic transducer, the electrical pulse generator, usiliteA, switch, 'frequency multiplier, a mixer, a frequency, integrating veno generator with sine krebany varikapnymi v'kolebatelnom loop and an amplitude detector.' output device P1 <. "

Closest to the proposed technical essence is a single-channel ultrasonic flow meter containing a transducer with two pieoelectric elements connected via a switch to a pulse generator ^w and an amplifier with a delay line connected to the control input of the pulse generator, but connected to a multiplier, a reversible counter, a storage unit, and an output block, and the input of the multiplier is connected to the output of the pulse generator, a crystal oscillator, a frequency divider and a pulse shaper Rania, the input of which via a frequency divider and a crystal oscillator connected to the switch, and the second output of the frequency divider coupled to the second input of the memory unit [2J. The disadvantage of these ultrasonic flow meters is their low noise immunity due to the possibility of short-term emission indications caused by the appearance of gas pulses in a controlled fluid or by single electrical impulse noise.

The purpose of the invention is to increase the noise immunity of the flow meter.

This goal is achieved by the fact that a series-connected low-pass filter is introduced into the flowmeter

I that additional amplifier, co-ownership circuit and trigger, the output of which is connected to the third input of the storage unit, when ed, the input of the low-pass filter * is connected to the output of the frequency multiplier, and the output of the locking pulse generator is connected to the input of the reverse counter and with the second input of the match pattern.

The drawing shows a block diagram of the proposed flow meter ..

The flow meter contains a converter 1 with two piezoelectric elements 2 and 3 connected to a pulse generator 4 and an amplifier 5 through an electronic switch 6, a delay line 7, a frequency multiplier 8, a crystal oscillator 9, a frequency divider 10, a low-pass filter 11, an additional amplifier 12, coincidence circuit 13, ₍ trigger 14, pulse shaper locking 15, the reversing counter 16, the storage device 17 and the output device 18.

The device operates as follows.

In the electro-acoustic circuit, consisting of a pulse generator 4, a transducer 1 with piezoelectric elements 2 and 3, an amplifier 5 and a delay line 7, the pulse repetition rate is set equal to ^ c ^ the radiation of the ultrasound in the flow at and for where cL _£ _ tv-eosd.

^f -v ~ ---- g ---- radiation against the flow, sound propagation velocity ^ in a controlled environment; flow rate;

the distance between the piezo. cops;

the angle between the direction of the ultrasound beam and the axis of the pipeline.

The repetition frequencies f ₊ y and fy alternately arrive at the frequency multiplier 8. In the absence of a gas bubble *. In a controlled environment, each of the repetition rate multiplied by n times is fed to a reverse counter 16, in which for a given time interval T, the difference in the number of pulses proportional to the flow rate is counted

AN "" (f ₊ y - f-y) pT.

This difference transmits to the storage device 17 each cycle of the flowmeter, including the radiation time

872965 4 downstream and upstream. The output device 18 converts the resulting difference into a unified output signal

K (f. _V - Cy) · η -T.

In the presence of gas bubbles in a controlled environment or during short-term electrical interference at the output of the multiplier 8 at the time of failure of synchronization, low-frequency oscillations occur, which pass through the low-pass filter 11 to an additional amplifier 12 and from it to one of the outputs of the matching circuit 13.

At the second input of the coincidence circuit, rectangular pulses from the pulse shaper of locking 15 are received. Provided that the input of the coincidence circuit of rectangular pulses from the chain 11-12, a signal is generated at the terminal of the coincidence circuit, which is fed to trigger 14 and throws it to the position at which * the voltage is forbidden, which prohibits the storage device from receiving false information from the reverse counter 16. In the other case, the device receives information on the flow rate of the previous cycle . At the beginning of a new operation cycle of the flowmeter, set by electronic switch 6, the trigger is set to its initial position and remains in this position until the next synchronization failure of the pulse generator 4. If there are no interruptions, the trigger is always in the initial position, and the memory inhibit signal is not received.

Thus, the indications of the proposed flowmeter are more responsive when the flowmeter is operating in conditions of increased gas contamination and contamination of the controlled environment, as well as in the presence of electrical noise, which disrupt the synchronization of the pulse generator.

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2 $

Claims (1)

The invention relates to instrumentation, namely, ultrasonic measuring instruments, and can be used to measure. Rheni flow of liquids. - A single-channel ultrasonic flow meter is known, containing an ultrasonic transducer, an electric pulse generator, a ycraniTejft, a commutator, a frequency multiplier, a StenHTenb frequency meter, an integrating Bveno, a sinusoidal oscillator with a varicap oscillator in an oscillatory circuit, an amplitude detector and. output device P1 Closest to the proposed technical entity is a single-channel ultrasonic flowmeter containing a transducer with two devices: two elements, connected via a switch to a pulse generator and an amplifier with a delay line connected to the control input of the pulse generator, sequentially connected multiplier, reversible counting, memorization of the block and the output block, with the input of the multiplier connected to the output of the pulse generator, crystal oscillator, frequency divider and spruce blanking pulses, the input of which via a frequency divider and a crystal oscillator connected to the switch, and the second frequency divider connected to the second input of the memory unit 23. The disadvantage of these ultrasonic flow meters is their low noise immunity due to the possibility of short-term emissions of indications caused by the appearance of gas bubbles in a controlled fluid or single electrical impulse noise. The purpose of the invention is to improve the noise immunity of the flow meter. The goal is achieved by introducing a series of low-frequency TTTs, an additional amplifier, a condominium scheme, and a trigger, the output of which is connected to the third input of the storage unit, when the low-frequency filter input is connected to the output of the frequency multiplier, and the output of the pulse former locks connected to the input of the reversible counter and with the second input of the coincidence circuit. The drawing shows the block diagram of the proposed flow meter. . The flow meter contains a transducer 1 with two piezoelectric elements 2 and 3 connected to a pulse generator 4 and an amplifier 5 through an electronic switch 6, a delay line 7, a frequency multiplier 8, a crystal oscillator 9, a divider 10 its frequencies a low frequency filter 11, an additional amplifier 12 , coincidence circuit 1 trigger 14, pulse shaper lock 15, reversible counter 16 memory 17 and output device 18. The device works as follows. In an electroacoustic circuit consisting of a pulse generator 4, a transducer 1 with piezoelectric elements 2 and 3, an amplifier 5 and a delay line 7, the tracking frequency and pulses are set to 4V 6 when the flow of ultrasound and f C.V.COSd. T-V g With upstream radiation, where C is the speed of sound in a controlled environment; Vf - flow rate; B is the distance between the piezoelectric. cops; cL is the angle between the direction of the ultrasonic beam and the axis of the pipeline. The following frequencies and f.y are alternately fed to a frequency multiplier .8. In the absence of gas puyir. in a controlled environment, each of the follow frequency multiplied n times is fed to a reversible counter 16, in which for a given time interval T is counted proportional to the flow difference of the number of pulses AN (f4.v - f-v) PT. . This difference transmits to the memory unit 17 each cycle of operation and a flow meter, including the time of radiation downstream and upstream. Output device 18 converts the resulting difference in a unified output signal K (f-v - -v) P-m. Cree gas presence in a controlled environment or during short-term electrical interference at the output of the multiplier 8 at the time of synchronization failure low-frequency oscillations occur, which flow through the low-pass filter 11 to the additional amplifier 12 and from it to one of the outputs of the matching circuit 13. To the second input of the circuit coincidences are received by rectangular impulses from the pulse shaper I5, subject to the input to the input of the coincidence circuit of rectangular pulses from the string 11-12 at the output of the coincidence circuit A signal is triggered, which arrives at trigger 14 and transfers it to a position in which the voltage is removed from it, prohibiting the memory device from receiving false information from the reversing counter 16. In this case, the output of the device receives information on the flow rate of the previous flow meter operation. At the beginning of a new cycle of operation of the flow meter, set by the electronic switch 6, the trigger is set to the initial sex and is in this position until the next disruption of the synchronization of the pulse generator 4. In the absence of disruptions, the trigger is always in the initial position, and the memory barring signal does not arrive. Thus, the indications of the proposed flow meter are more effective when the flow meter is operating under conditions of high gas content and pollution of the controlled medium, as well as in the presence of electrical noise, which causes a breakdown of the generator timing synchronization. Claims of the invention A single-channel ultrasonic flowmeter comprising a transducer with two piezo elements connected through a switch to a pulse generator and an amplifier with a delay line connected to the control input of the pulse generator, a successor