SU494692A1 - Method for measuring fluid velocity - Google Patents

Description

The measurement relates to the field of measuring telescopic techniques and can be used to measure the velocity of water in open, ordered channels.

A known ultrasonic method for measuring the velocity of the fluid 1 and the fluid is based on sounding the flow of the well in the direction of motion and against the ultrasonic vibrations. The velocity of a double fluid is determined from the frequency difference between the pulse-modulated oscillations directed along the flow and against it. The method eliminates the influence of the value of: italic changes in the speed of sound in the liquid under study. It is noted that the measurement accuracy in polluted railway stations is as low as it requires you to use: the frequency of radiation frequencies that experience strong fluctuations of a signal; M1 signal strength.

Purpose. the invention is an increase in the accuracy of -measurement. This is achieved due to the fact that the frequency-modulated linear-sawtooth radiation is emitted and received. Ultrasonic oscillations are completed, the beat frequencies between the emitted and received vibrations are determined from each direction and the speed of movement of the test liquid. For the sake of sharpening the changes in the base distances between the emission and reception points, the frequency deviation and the modulation frequency of such

Thus, the product of the frequency deviation by the frequency of modulation and the magnitude of the base distance remains constant.

FIG. Figure 1 shows the diagrams, g, t, the RELEASE line shows the law of variation of the frequency of the emitted signal F ,,, and the dash-dotted line shows the received P, which is shifted relative to the radiation of the signal, at T — time of the signal propagation from radiation to receive.m1 ) i1ka.

When mixing the emitted and received signals, the frequency of beats / o is released, which is defined as

F1

/ b, or GB-ug-f. (one)

t4 G - / t

four

20

where AF is the maximum frequency deviation from the mean (frequency deviation);

fm, Tm is the frequency and period of modulation of the signal (frequency and period of the sawtooth voltage).

Denote by 1 time the propagation of the signal from the radiator to the receiver downstream, 30 versus -G, then

T. - T ----- (9)

 , C A-V with - I /

where L is ras-sto 1 e between the radiator to the right n: ohm;

C-speed of sound in a liquid; V-velocity of fluid. Proceeding from this, for a signal that propagates through the gyutoku, we have

 „1C- -V.,.

  - 4Af ,, ,,

and for dl, spreading protpz flow;

1C - V

7 .С4.

“-, l / g. f 7. - /

 I „1 1 -t-i / I gp i

Razaosnost periods composes

T, + Gb - 2d 7.- From here

V 2if- / „LCre -n -). (B)

E | S; to the direction of propagation of the signal is with the angle of the movement of the liquid angle 9, then

9AF. f I cose - - --P)

KaiK can be seen from the formula (7), the value of V is completely independent of C - the speed of sound in a liquid, but depends on the parameters of the device & F, fm- They allow you to measure with high accuracy at high values of a independently from stepg; -ai and contamination of the liquid, since the operating frequency can be chosen in the range where the attenuation of ultrasound is relatively small. In addition, when measuring on channels

different compensation of the variation of the baseline array between the radiating and n-receiver elements. M1i can be easily implemented by changing the frequency deviation AF or often T modulation /, so that the product LR / m-b remains constant for different L.

N. and cbj; r. 2 is a block diagram, but is shown in sync. Inputs of master oscillators

1 I 2 Sigals FI and P2 are connected to the outputs of the modulator 3, and the outputs are to radiators 4 and 5 installed on the opposite walls of the channel at the same level and to the inputs of mixers 6 and 7. To other inputs of the mixers

and 7 are connected to the receiver 8 in 5, and the outputs of the mixers are connected to the input of the solving circuit 10 with the indicator 11. Frequencies are generated at the outputs of the mixers, and ff + - are fed to the input of the circuit 10. The count is derived from the Hia indicator directly in the speed unit.

Subject, and d about e and ;;

Claims (2)

1. Ultrasonic crioco6 and alternate fluid velocity, asnag1 & on sensing fluid flow in the direction of motion, and against ultrasound shi and oscillations; and mi, about tl-and h and y, and with the fact that, with In order to improve the accuracy of s.merenny, they emit, and ultrasound oscillations that are frequency-modulated according to the linear-ori-shaped law are used, the frequencies of beats between the radiation and the frequency are determined in each direction; The 1M1I prints by oscillations and the difference in the periods of beats determine the speed of the movement; 2. Ultrasonic method according to claim 1, which is based on the fact that, with the aim of composing: a change in the base distances between points. radiation and reception, they change the frequency deviation K the frequency of modulation so that the product of the frequency deviation by the frequency of modulation 1I by lead: the frequency of the base distance remains constant. H J  / f / / tp c, / /. Y -7 / G / / f f / f / G7 7 ////// 7.