SU781581A1 - Astable liquid flow double-channel electromagnetic flowmeter - Google Patents

Description

frequency distortion, since it is difficult to choose the transmission coefficients with the same amplitude-fae-frequency characteristics.

Due to the EFFECT of transformer noise in an alternating field transducer, additional measurement measurement occurs. Errors in known devices arise from the fact that multiplying devices on both active and passive elements are realized approximately.

11 known devices besides these drawbacks are also functionally limited only by converting the magnitude of the flow into an electrical voltage and not from the spectral characteristics of the flow. For this, an additional spectrum analyzer is needed in these devices which introduces an additional error in measuring the spectral characteristics of the flow rate.

The purpose of the invention is to improve the measurement accuracy by seeking transformer interference and obtaining the spectral characteristics of the flow.

This goal is achieved by the fact that a two-channel electromagnetic flowmeter of unsteady fluid flow containing a pipeline section, flow transducers placed on it, a power supply system for flow transducers, an amplifier in each channel is equipped with a frequency controller (magnetic field oscillations, each channel is equipped with series-integrated integrator and averaging and a voltage meter at the output, and the output of each amplifier is connected to the input of the integration and averaging unit,

A two-channel electromagnetic flow meter of unsteady fluid flow contains a section of pipeline 1, on which are placed electromagnetic flow transducers 2 and 3 with sinusoidal magnetic fields that are quarter-period displaced relative to each other by a period. The magnetic field in both transducers is excited by block 4, and the frequency regulated by frequency knob 5. Converters 2 and 3 of flow in each channel are connected respectively to amplifiers 6 and 7 of alternating current, the outputs of which are connected to the inputs of blocks 8 and 9 of integration and averaging. Outputs of blocks 8 and 9 Intyog | The jumper and the terminal are connected to the inputs of the 10 and 11 voltages. provides for the conversion of x 2 and 3 sinusoidally varying in time magnetic fields shifted relative to each other by a quarter of the period.

When fluid flows through the pipework 1, some of the signals with

converters 2 and 3 are amplified by amplifiers b and 7 of alternating current. Preliminary by means of regulator 5, the frequency is set to frequency (Wg magnetic field, then at the output of amplifier 6 and 7 the signals are respectively

and K sinu / gtQCt) + K, sinuu t (YO sinew t + EQ% coisiw t) + +, - (2) Uj. Kj costw.tQ (t) + CjSinte t K-jCosuUg trc Q siniiJ t (t) + + C j siniWgt., (3)

(n 1, N) are integers),

where C cosowgt; C sin t - transformer interference;

Qj; Q is the amplitude of oscillations of the flow of the n-th spectrum; TSU - circular frequency n-th

spectrum,

 transmission ratio of the first channel;

K „is the transmission coefficient of the first converter; K - transfer coefficient of the first amplifier,

  transmission coefficient of the second channel;

K - transfer coefficient of the second converter; To - transfer coefficient

 The second amplifier, the flow signals, amplified by amplifiers 6 and 7, are fed to the inputs of blocks 8 and 9 of integration and averaging. At the output of blocks 8 and 9, the signals are respectively

t

from

about l)

-) t) lt .Qe, G °

TK TK °% H «« «« «p.

oo

+ Qjcbsou tjdt - | - {Cj StnU gtdt i-K.Qg

- four

 by virtue of the properties of orthogonal Functions-Ttions, n conditions

t 1, 2 ,,, N);

Output signals (4) and (5) blocks

8 and 9 act on the meters 10 and c voltage,

Yokaiani meters are processed in the following order: the values (4) and (5) obtained by the VDD & Tcr are scaled by dividing the output signal of the block 8, respectively, by the value of the input signal of the block 9.

According to Q / f J values

and Q / p calculate the amplitude of fluctuations of the flow of the spectrum spectrum

Q

(6)

VQ + oscillation phase

tfCiOjj. arctg-Q (7)

NLP spectral power S (iO) / Qg)

JaveM by means of frequency adjuster 5 sets another magnetic field frequency and the procedure for measuring the amplitude and phase of the flow oscillations already for other frequencies is repeated in sequence.

In the proposed device, the influence of transformer interference is eliminated automatically by choosing either a sufficient integration duration or selecting an integration duration multiple to the frequency of the magnetic field, which leads to an increase in the measurement accuracy,

Claims (2)

1. Korsunsky L.M. Electromagnetic hydrometric devices. 2Q M., 1964, p. 58-61. , 2. USSR author's certificate 561089, cl. G 01 F 1/58, 1975 (prototype).