SU1364882A1 - Ultrasonic time-frequency flowmeter - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve the accuracy and simplify the flow meter prediction. The pulses of the generator 1 through the switch 3, the coincidence circuit 14 and the installation circuit 15 during the time of the permissive pulse of the driver 13 arrive at the counter 16, and the output of which sets a code equal to the value of the multiplication factor. This code is rewritten into divider 4 and measuring device 24, in which the flow rate is determined from the difference frequency values from the output of circuit 21. The device allows you to automatically set the internal multiplication factor and carrier frequencies of the controlled oscillators 1 and 2 depending on the diameter of the sensor and the speed of propagation of ultrasonic waves, providing a large range of operation of the device. 2 Il. i (L

Description

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The invention relates to a measurement technique and can be used to measure the flow rate of various liquid media.

The purpose of the invention is to improve the accuracy and simplify the operation of the flow meter.

FIG. shows a schematic block diagram of a flow meter; 2, time diagrams of signals at points in a flow meter circuit.

The flow meter consists of controlled generators 1 and 2, connected via the first switch 3 to the input of a divider 4 frequencies; shaper pulse 5, the second 6, third 7 and fourth 8 keys, amplifier-shaper 9, the input connected to the output of the third key 7, clock distributor 10, the input connected to the output of the splitter 4 frequency and the outputs of the shaper puller 5 and through it with the input of the second key 6, as well as with the switch 11; time selector 12, the inputs connected to the inputs. the clock distributor 10 and the amplifier-amplifier 9 receiving signals, and the output connected to the input of the fourth key 8; a driver 13 time intervals, having inputs connected with one of the outputs of the clock distributor 10 and with one of the outputs of the amplifier forming 9; circuit 14 coincided 1g connected by one input to the output of the imaging unit 13 time intervals, and their other input connected to the input of the divider 4 frequency; an internal multiplication setting circuit 15 (e.g., an OR circuit), one of the inputs connected to a coincidence circuit 14; a first reversible counter 16 controlling the division ratio of the 4 frequency divider; the third 17 and second 18 reversible counters control the second 19 and first 20, respectively, frequency control circuits of generators 1 and 2, the inputs of counters 7 and 18 being connected via a key to the time selector 12, and the second output of the second counter 18 is connected to the input of the installation circuit 15 internal multiplication factor; difference frequency allocation circuitry 2 1, the inputs of which are connected to the outputs of generators 1 and 2; transceiver converters 22 and 23, connected via keys 6 and 7, respectively, with

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worldwalker 5 probe pulses and amplifier 1 d shaper 9; the measuring device 24, one input of which is connected with the output of the first counter 16, and the second with the output of the differential-frequency-sharing circuit 21.

The flow meter works as follows.

The controlled generators 1 and 2 produce pulses with the following periods Tj and T, (fig.2a, g). Previously, with switch 11 signals, keys 3 and 6-8 are switched to the USI emission mode, for example, downstream. Generator 1 pulses through the key 3 is fed to a frequency divider 4 with a division factor of p, at the output of which signals appear

(FIG. 26} O. The first one through the clock distributor 10, the driver 5 of the probe pulses and the key 6 is sent to the transmitter converter 22 (FIG. 2b), the ACW, the passage through the measured liquid is received by the converter 23 and through the key 7, the amplifier-shaper 9 (FIG. 2c) is fed to the input of the time discriminator 12, where it is compared with the reference signal

scrap coming from the second output of the clock distributor 10 (FIG. 2d). Further, depending on the temporal location of these two signals through key 8, counter 18, digital-analog

The converter 20 controls the frequency of the pulses of the generator 1 until the reference and receive signals coincide. By an impulse from the third output of the clock distributor 10 (Fig. 2e, c), switch 1 switches the whole circuit to radiation upstream mode. The cycles described are repeated (Fig. 2g, e). When the flow meter is first turned on.

It is essential to select and set the value of the internal multiplication factor. For this purpose, in one of the modes of radiation by ultrasound, for example, downstream, the former 13 forms

for circuit 14 coincidence pulse

(Fig. 2d) with a duration equal to the time of passage of the ultrasound in the sensor. The pulses of the generator 1 through the key 3, the circuit 14 of the match and the circuit 15 of the installation

only during the time of the action of the permitting pulse of the imaging unit 13 is sent to the counter 16, the output of which sets a code equal to the value of the internal multiplication factor.

those. PS This code is then rewritten to divider 4 and measuring device 24, the value of the flow rate is determined at the last difference difference frequency values from the output of circuit 2, coefficients n and transformed (determined during calibration of the flow meter).

In the event of a change in the flow meter physicochemical parameters of the measured fluid, the speed of the ultrasonic scan can differ significantly from the initial value at which the value of the coefficient P is determined. In this case, the controlled generators can operate on the nonlinear part of the characteristic their restructuring. Then there is a need to adjust the value of n in order to ensure the functioning of the generators in a narrow range of tunable frequencies. For this purpose, an additional channel of automatic control of the internal multiplication factor is introduced into the flow meter, which operates as follows.

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five

tee on sensor diameter and speed

propagation of ultrasonic waves

providing a wide range of work

devices.

Claims (1)

Invention Formula An ultrasonic time-frequency flow meter containing a flow sensor with two transceiver transducers, the first and second controlled generators, a shaper of pulses, a clock distributor, a booster of receiving signals, a time selector, a differential frequency selection circuit generators, a frequency divider, the first, second and third keys, a switch and a measuring device connected to the difference frequency allocation circuit, the inputs being controlled the generators are connected to the outputs of the respective control circuits, and the outputs are connected to the output circuit of the differential frequency and through the first switch and frequency divider with a clock distributor, which is connected to the time selector, switch and through the driver Previously, in the counter 18, there are 30 pulses - with the second key, connected a number is cast, the value of which depends on the tuning range and steepness of the characteristics of generators 1 and 2, In tracking mode, depending on the temporal location of the receiving and reference pulses on the time discriminator 12 (fig, 2d, k) pulses or subtracted or added from the set value, thereby providing the required frequency of the oscillators. When the speed of the ultrasonic inspection changes at the input of the counter 18, loan impulses or overfillings can be generated, which, through the installation circuit 15, arrive respectively at the summing or subtractive inputs of the reversible counter 16 t, e, in the divider 4 and the measuring driver, and the output through the circuit Code 24 is set to (+1) or (-1). Thus, the generators 1 and 2 are operated in a narrow frequency range, The device allows you to automatically set the internal multiplication factor and carrier frequencies of the controlled oscillators to dependent With a transceiver transducer, which is connected to the time selector via the third key and the driver –former, so that, in order to increase accuracy and simplify operation, it is equipped with a time interval former, a coincidence circuit, the installation scheme of the internal multiplication factor, the first, second and third reversible counters, the fourth key, and the time selector through the fourth key is connected to the second and third reversing counters, each of which is connected to one from the generator control circuits, and the driver of the time intervals of the inputs is connected to the clock distributor exits and power - the coincidence connected by the second input to the output of the first key — with the first input of the circuit for setting the internal multiplication factor, connected by the second input to the second reversible counter, and the output through the first. meter with measuring device and frequency divider.