SU1530916A2 - Ultrasonic flow meter - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the flow of liquids and gases. The aim of the invention is to improve noise immunity and reliability when measuring non-uniform flow. When the medium moves through the flow transducer, the frequency of the circulations in the synchroable rings will differ by ΔF. If there are extraneous inclusions in the flow and disruption of the autocirculation in the flow meter, the circulation process is restored by applying a synchronizing pulse to the input of the generator 4 from the output of the divider 23 through the delay block 30, element 32 OR, and the one-shot 34. This pulse comes instead of the missing from the output of circuit 6 and replaces it in functionality. A difference between them a delay T equal to the duration _of the time delay unit 30 and can be extremely small. The fault signal from the output of the trigger 40 sets the frequency meter to the zero state and disables counting until the end of the fault signal. When autocirculation is restored due to the arrival of information from the output of shaper 10 to the second input of flip-flop 40, the signal is cleared. 2 Il.

Description

Decides to count before the end of the signal failure. When restoring autonircula, due to the receipt of information

From the output of the driver 10 to the second input of the trigger, the AO signal is cleared. 1 zp. Lg-ly, 2 ill.

The invention relates to a measurement technique, can be used to measure the flow rate of shadcos and gases and is an improvement of the invention according to the author. N P6A551.

The purpose of the invention is to improve the noise immunity and reliability of the ultrasonic flow meter when measuring the flow rate of a non-uniform flow.

On league. shows a structural diagram of an ultrasonic flow meter; On Lig.2 - a flowmeter frequency circuit.

The ultrasonic flow meter consists of a measuring section 1, two reversible electroacoustic transducers 2 and 3, two syncro-ring circuits including generators 4 and 5, the first circuits 6 and 7 coincidence, the second circuits 8 and 9 coincidences, the formers 10 and 11, amplifiers 12 and 13, the first triggers 1A and 15, the first single vibrators 16 and 17, as well as the third 18 and fourth 19 coincidence circuits, the second trigger 20, phase discriminators 21 and 22, the first frequency dividers 23 and 2A, the circuits 25 and 26 are blocked, controlled oscillators 27 and 28, unit 29 for making frequency differences.

Blocks 30 and 31 delays are entered into each synchro-ring, the first elements are OR 32 and 33, the second one-shooters are FOR and 35, the fifth coincidence circuit 36 and 37, the second dividers 38 and 39, the third triggers AO and A1, the outputs of the latter are combined by the OR OR A2 element. To the first A3 and second AA output terminals of the ultrasonic flow meter is connected the frequency meter A5, which contains (figure 2) timer A6 (performed, for example, in the form of a synchronized autogenerator ra, the synchronous input of which is connected to the input of timer Ab), element OR A7, counter A8 A9 decoder and indicator 50.

An alarm device (not shown) can be connected to the first output terminal A3 of the ultrasonic flow meter.

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light (for example, LED) or sound (for example, bell)

The flow meter works as follows.

The pulse of the generator And is supplied to the transducer 3, which emits an ultrasonic pulse downstream. Passing through the measuring medium, the pulse arrives at converter 2 and is amplified by amplifier 12. The front of pulse 10 of the transmitter 10 through coincidence circuit 6, the OR 32 element and the one-oscillator ZA starts generator A, then the process repeats. The trigger 1A is in such a state that the coincidence circuit 6 misses, and the coincidence circuit 8 misses the pulse from the driver 10.

The pulse from the generator 5 is fed to the Converter 2, which emits a pulse against the flow. The pulse received by converter 3 is amplified by amplifier 13 and is formed by shaper 11 into a rectangular pulse. The pulse generator of generator 11 through the coincidence circuit 7, the element OR 33 and the one-shot 35 start the generator 5, then the process repeats. The trigger 15 is in such a state that the coincidence circuit 7 misses, and the coincidence circuit 9 misses the pulses of the driver I1. When the medium moves through the flow rate converter, the circulation frequency in the synchroable rings will differ by 4f.

When the pulse of the generator A coincides with the pulse of the driver 11 at the output of the coincidence circuit 19, a pulse is generated that flips the trigger 20, operates in the counting mode, and another state. The pulses of the trigger 20 overturn the trigger 1A in a state where the coincidence circuit 8 transmits the pulses of the driver 10 to the single-vibrator 16, and the coincidence circuit 6 does not pass the pulses of the driver 10 at the input of the generator A. The one-shot 16 triggers the pulse of the coincidence circuit 8 and generates a pulse. A pulse 4 of the one-shot 16 starts a generator 4, the pulse of which returns the trigger 14 to its initial state, and the operation of the sync ring repeats cyclically.

In the absence of a pulse from the one-shot 16, the prohibition circuit 25 transmits the pulses of a controlled generator 27 to the input of divider 23. Phase discriminator 21 analyzes the relative temporal position of the pulses fed to it from generator 4 and divider 23, and outputs a control signal controlled by generator 27. that the frequency at the output of divider 23 is equal to the frequency of the generator 7, and the phase difference of these signals is constant ..

In the case of the presence of extraneous inclusions in the measured flow and in the case of autocirculation, the following processes occur in the synchro-ring circuit in the ultrasonic flow meter.

The circulation process is restored by supplying a synchronizing pulse to the input of the generator 4 from the output of the divider 23 through the delay unit 30, the OR 32 element and the single-oscillator 34. This pulse comes in place of the missing match from the output of the circuit 6 and replaces it by function. Moreover, the difference in time between them (otherwise, these pulses are identical) is equal to the duration of the delay time TU of the delay unit 30 and can be extremely small, since it is selected and determined mainly by the duration of the generator 4 impulse.

Thus, an artificially created autocirculation has a period as close as possible to the period of the normal autocirculation process (the difference is by the amount of delay T of the block 30 delay). In the absence of failures due to extraneous inclusions, the km-pulse at the output of the delay unit 30 (and, accordingly, at the output of the OR element 32) is also formed, but it is not perceived by the one-shot 34, the latter being triggered by a pulse without delay (i.e. Tj), and its pulse duration is chosen to be longer than T (during the generation of the pulse, the one-shot does not respond to input signals).

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The coincidence circuit 36 controls the autocirculation process and in the case of its accumulation (i.e., when an artificial autocirculation process occurs), a signal is generated at the output, since the signals at its input coincide (generator 4 is triggered by the leading edge of the one-shot 34). In the absence of a second divider 38, the trigger 40 is immediately set to match; This is the result of autocirculation. The signal from its output through the second element OR 42 enters the output 43 of the device. In the presence of the second divider 38, the signal at the input or, respectively, at the output of the trigger 40 is delayed by the corresponding division factor of the second divider 38 number of artificial autocirculation petriods, which is necessary in some cases (for example, with a tolerance of measurement error in K T, μs). A fault at the output of the trigger 40 is removed when autocirculation is restored due to the arrival of information from the driver 10 to the second input of the trigger 40. The alarm from the output of three triggers 40 sets the frequency meter 45 to zero and disables counting until the end of the alarm. The same signal can be supplied to a detector (not shown) about the auto-circulation ratio or used in other devices (for example, information processing) connected to the output terminals 43 and 44 of the ultrasonic flow meter.

The second synchro-ring works in a similar way when reversing the flow.

The signals from the controlled generators 27 and 28 are sent to the block 29 by selecting: neither the difference frequency, the output of which produces a frequency proportional to the flow rate and measured by the frequency meter 45.

Frequency meter works as follows.

The counter 48 counts the pulses arriving at the second input of the frequency meter 45. The timer (t) 46 periodically generates the counting time, for example, 1 s (the counting time is equal to the pause between pulses T 46). On the leading edge of the pulse T 46, the decoder 49 remembers the information on the start of the counter 48, the indicator 50 indicates it, and

cutoff pulse T 46, the counter 48 starts counting from zero (since the first input of the counter 48 is set to zero) of a new sequence of pulses. When a fault signal is received at the first input of the frequency meter 45 that prohibits the counting of pulses, the counter 48 is set by this signal to the zero position. T 46 is braked (stopped) by strobing dega- arator 49, which leads to an indication of a zero code at the output. When the signal is removed from the first input of the frequency meter 45, the process is a periodic counting of the number of input pulses. at the second input of the frequency counter 45, i.e. the measurement of their frequency is resumed (restored) as the T 46 goes into oscillator mode.

As a decoder 49, a K176ID2 microcircuit can be used, and as an indicator 50, a cost center indicator.

. Thus, the frequency meter 45 measures the difference frequency proportional to the flow rate of the liquid, thus excluding the erroneous measurement result in the event of a failure in the synchro-ring circuit.

The use of the proposed flow meter makes it possible to increase the reliability and accuracy of measuring the flow of liquids and gases by eliminating erroneous results and by artificially maintaining autocirculation in the synchrock circuit at the moments of its malfunction with a frequency as close as possible to K | , the frequency of natural autocirculation, t, which gives a minimal error and deviation from the real value of the flow of a non-uniform flow.

At the same time, if necessary, a more accurate measurement of the flow rate and the possibility of half the result of approximating the measurement results and using only the measurement results in the absence of faults (with the exception of the splitters or the adjustment of their division ratio)

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The application of the proposed flow meter, for example, in amelioration allows for more accurate accounting of irrigation water, thereby achieving its economy and irrigation of additional areas, which gives a significant economic effect.

Claims (2)

1. Ultrasonic flow meter, according to author. J 1164551, characterized in that, in order to improve noise immunity and reliability when measuring the flow of a non-uniform flow, synchro-rings are inserted into it, sequentially connected to the delay unit, the first OR element and the second single-coupler, as well as sequentially connected fifths the coincidence circuit, the second divider and the third trigger, and the input of the delay block of each sync ring circuit is connected to the output of the corresponding first divider, the second input of the first OR element - to the output of the corresponding first circuit is the same and, and the output of the second single clock is connected to the input of the corresponding generator, the inputs of the fifth coincidence circuit are connected to the output of the corresponding delay unit and the input of the phase discriminator, and the second input of the third trigger is connected to the output of the corresponding second matching circuit, while the outputs of the third trigger both The sync ring is connected to the inputs of the second OR element, the output of which is the second output of the device. 2. The flow meter according to claim 1, about tl and - due to the fact that it is equipped with a frequency meter, made in the form of serially connected timer, OR element, counter, decoder and indicator, the timer input and the second input of the OR element are connected to the second output of the device , the first output of which is connected to the second input of the counter, and the second input of the decoder is connected to the output of the timer. K KMMffe J / (/ (e e44fPuf .2