SU1081544A1 - Ultrasonic meter of flow pulsing speeds - Google Patents

Abstract

ULTRASONIC PULSING FLOW SPEED MEASURES, containing two reversible electroacoustic transducers connected through a switch to the transmitter and receiver of pulse signals, a time interval digital converter, the output of which is connected to the first subtractor unit, synchronizer and recorder, the same pattern that the disconnect pattern is used. in order to increase accuracy and increase measurement speed, it additionally introduced two voltage amplifiers, the second subtraction unit, analog registrar , integrator, two analog-to-digital converters, two blocks:, -, square root root extractor, f I i mrfEHAf, ratio calculator and multiplication unit, the inputs of the second subtraction unit being connected to the switch, its first output is via analog the recorder and the first analog-to-digital converter and the square root extraction unit are connected to the first input of the multiplication unit; its second output is through the integrator and the second analog-digital converter and the square root extraction unit are connected It is connected to the second input of the ratio calculation unit, the first input of which is connected to the output of the first subtraction unit, and the output j to the second input of the multiplication unit whose output is connected to the recorder, while the input of the time-to-digital converter is connected to the output of the receiver of pulse signals, and the synchronizer outputs are connected to the control inputs of the switch, transmitter and receiver of pulse signals, time-digit converter, dividing unit, first subtraction unit, analog recorder and ana th-to-digital converters. D1

Description

The invention relates to acoustic measurements and can be used to measure the velocities of pulsating flows, as well as in monitoring the progress of technological processes and controlling the dynamic velocity flow. A device is known to be measured by a pulsator of dukh flow velocities, containing electroacoustic transducers, a receiver of pulse signals, a transmitter of pulse signals, a switch, switched on a synchro-junction circuit, and recording a block ij. The disadvantage of this device is the limited measurement performance, which virtually excludes the possibility of measuring fast pulsations of the flow velocity, since a reliable interval of pulse repetition rates in synchrocats requires a large time interval. The closest to the invention to the technical essence is an ultrasonic pulsating flow velocity meter containing two reversible 3JjeKTpoaKycTH4ecKHX transducers connected via a switch to a transmitter and a receiver of pulse signals, a pulse generator, a shift register, a computing device, a time interval converter — a digit whose output is through the dividing unit is connected to the subtraction unit, the synchronizer and the recorder 2. A disadvantage of the known device is the limited accuracy of the measurement performance during operations with pulsating flows. The aim of the invention is to improve the accuracy and increase the speed of measurements. The goal is achieved by the fact that, in an ultrasonic pulsating flow velocity meter containing two reversible electroacoustic transducers connected through a switch to a transmitter and receiver of pulse signals, the time interval transducer is a digit whose output in the dividing unit is connected to the first subtraction unit, synchronizer and recorder, additionally introduced two voltage amplifiers, the second subtraction unit, analog recorder, integrator, two analog-to-digital converters, two blocks square root extractor, ratio calculating unit and multiplication unit, the inputs of the second subtraction unit through voltage amplifiers are connected to the switch, its first output is through an analog recorder and the first analog-to-digital converter and the square root extractor are connected to the first input of the multiplication unit, its second the output through the integrator and the second analog-to-digital converter and the square root extraction unit are connected to the second input of the ratio calculation unit, the first input of which is connected to the output of the first subtraction unit, and the output to the second input of the multiplication unit, the output of which is connected to the recorder, while the input of the time interval converter is a digit connected to the output of the receiver of pulse signals, and the outputs of the synchronizer are connected to the control inputs of the switch signals time converter is a digit, dividing unit, first subtraction unit, analog recorder and analog-to-digital converters. Figure 1 presents the block diagram of the ultrasonic meter pulsating flow rates; 2, diagrams showing his work. The meter contains two reversible electroacoustic transducers 1 and 2, switch 3, receiver 4 and transmitter 5 pulse signals, time converter 6 is a digit, division unit 7, first subtraction unit 8, synchronizer 9, two voltage amplifiers 10 and 11, second unit 12 subtractors, an analog recorder 13, an integrator 14, two analog-to-digital converters 15 and 16, two blocks 17 and 18 of square-root extraction, a ratio calculation block 19, a multiplication unit 20, and a recorder 2J. Ultrasonic meter pulsating flow velocity works as follows. In the first cycle of each measurement cycle, the controlled flow is probed with acoustic pulses emitted sequentially in time by reversible electroacoustic transducers 1 and 2 in the direction of flow and against the direction of flow. The probe pulses are output from the transmitter 5 pulse signals through the switch 3 and are received by the receiver 4 pulse signals. The operation of the receiver 4 of the pulse signals, the transmitter of the 5 pulse signals and the switch 3 is controlled automatically by the synchronizer 9. In this case, the time for the acoustic pulse to travel along the flow direction is determined by the expression C + Vcosoi where c) is the base distance between the electroacoustic converters 1 and 2; C is the ultrasound velocity in the flow being monitored; V is the average flow rate over a time interval of length Od 0 (, is the angle between the baseline and the direction of flow. The time the acoustic pulse travels against the direction of flow is determined by the expression. A b ct The received pulses from the output of the receiver 4 are pulsed. signals are input to the converter of the time interval 6 - digit, where the values are converted into proportional digital values. In dividing unit 7, the digital values Mm and M are converted sequentially over time into inverse digital I / HA and 1 / MBI values are fed to the input registers of subtraction unit 8. Time interval control of the converter b - the digit of division unit 7 and subtraction unit 8 is detected by synchronizer 9. The digital difference value from the output of subtraction unit 8 is written to the registers of the second the input of the ratio calculation unit 19. Thus, the average flow rate is determined in the interval | Averaging time, approximately equal to the duration of one half-cycle of measurement, i.e. the value of Sd. In the flows, the instantaneous velocity of which fluctuates relative to the average value of V according to the law V (t) (t), it is necessary to measure not only the value of V, but also the time dependence of the absolute change in the velocity l V (t). To do this, simultaneously with the control pulse of the synchronizer 9 between the emitted and received pulses, the switch 3 switches the electroacoustic transducers 1 and to the inputs of the voltage amplifiers 10 and 11. In the time intervals b, t (Fig. 2) between the emitted and received pulses in each measurement cycle on. The outputs of the amplifiers 10 and 11 receive voltages varying with time, proportional to the current hydrostatic pressure values from the emission zone of the acoustic impulse P, (t) and in its reception zone P (t) / which are fed to the inputs of the subtractor 12. The outputs of subtraction unit 12 in the intervals .t, ti continuously receive a voltage (t) proportional to the differential value (i) of the differential pressure i U, a) -bpU) pilt) -p2 (tb Dependence between the instantaneous value of uPCi) and the instantaneous speed V (1) is given by the expression & p (thi.) J (g) where K is a value depending on the physical characteristics of the flow and the distance between the emission zones and the reception of the probe pulses. The resulting time dependence of the voltage Ui (t) from the first output of the subtraction unit 12 is fed to the input of the analog recorder 13, where the time dependence of the voltage U (t) f is recorded proportionally; national pressure drop ip (t). The time dependence (i) from the second output of subtraction unit 12 is fed to the input of integrator 14, where it is averaged in analog form during the averaging time of cd. where ty is the effective duration of the probe pulse, and SC, i.e. Sd, Cj5-c5. According to (d), the averaged value of P is given by i PM.VUldl- K.V-. (d) .l The time dependence of the voltage U tj (t) obtained in the analog recorder 13 and in the integrator 14 is the average value (J - P, in the analog-digital converters 15 and 16 is converted to digital values uP (t) AP (t) and PP, and in square root extraction blocks 17 and 18, respectively, calculate the square roots Tf and P (I; T and Y, and-fp i | KV in each measurement cycle. Thus, in each Fth measurement cycle, one digital value Mts (Fig. 2) and one digital value. P ". In the ratio calculation block 19, the ratio coming from the output is calculated block 8 subtraction and the output of the square-root extraction unit 18 of the digital value Mc / - P | "-vl / TP in each h -th measurement cycle. Consequently, in kahsdom n-th measurement cycle, the value of m / iE ;; 17- , as well as a discrete belt sequence of digital values bl (.), during each interval and Cj between the sampling and received pulses. At this discretization step.) The dependence of dP (1) (Fig. 2) is determined only by the analog-digital converter. 15 and much less than the intervals C and tj Instantaneous flow rate V (i for example, at time ti in interval t (Fig. 2) is calculated as follows. The digital value of the DTHTTUT from the square-to-square extraction unit 17 and the digital value M / nfpJJ 1 / s of the ratio calculation unit 19 are transferred to the multiplication unit 20, which operates according to the algorithm 4 i7v -if -v tiV; -vit; 4. (e) The proposed first meter provides the ability to measure not only the average value V of the flow velocity with an averaging interval equal to d, but also measurements of discrete instantaneous values of the velocity at any 1 st time within the interval f d. This is achieved by introducing into the channel meter an analog measurement of instantaneous values of the pressure drop created by the flow in the areas of Two inverters of electroacoustic transducers and automatic compensation in the general case of an unknown parameter K. As a result, the coarse measurement error due to a change in K fluctuating flow. The speed of the meter through the measurement channel of discrete values of the instantaneous flow rate is increased at least 15-20 times. The use of the proposed ultrasonic meter of pulsating flow rates is especially useful in systems for automatically monitoring the state and control of systems for supplying liquid fuel power plants of aircraft.

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Claims (1)

ULTRASONIC PULSING FLOW SPEED METER, containing two reversible electro-acoustic transducers connected through a switch to a transmitter and a receiver of pulse signals, a time-domain-digit converter, the output of which through a division block is connected to the first subtraction unit, a synchronizer and a registrar, which differs for increasing accuracy and increasing the speed of measurements, two voltage amplifiers, a second subtraction unit, an analog recorder, integr are additionally introduced into it Torr, two analog-to-digital converter, two square root block, the block calculating the ratio and multiplying unit, the second input of subtraction unit cherez.usiliteli The stresses. Connections are connected to the switch, its first output through the analog recorder and the first analog-to-digital converter and square root extraction unit is connected to the first input of the multiplication unit, its second output through the integrator and second analog-to-digital converter and square root extraction unit is connected to the second input of the unit how to calculate the ratio, the first input of which is connected to the output of the first subtraction unit, and the output to the second input of the multiplication unit, the output of which is connected to the registrar, while the input azovatelya timeslot-digital receiver connected to output pulse signals, and the outputs of the synchronizer connected to the control inputs of the switch, the transmitter and the attraction emnika pulse signals, the time interval of the transmitter-digit division block, the first subtractor, an analog recorder, and an analog-to-digital converters.