SU1307389A1 - Device for measuring electric conductivity of liquid - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve the accuracy of measuring the conductivity of a liquid. The device contains a supply magnetic core (M) 1 with excitation winding 4, measuring M 2 with signal winding 7, alternating voltage source 3, phase meter, 12, while the studied electrolyte covers M 1 and 2 with short coiled coil 13. To achieve Targets are entered into the device by a capacitor 10, amplification 11 with a unit gain, and for each of M 1 and 2 two windings are introduced 5.6 and 8.9 respectively. 1 il. i (L 7t ato oo oo oo syo

Description

technology and can be used to measure the electrical conductivity of electrolytes.

The purpose of the invention is to increase the accuracy of measuring the conductivity of a liquid.

The drawing shows a diagram of the proposed device.

The device contains a supply magnet 1, a measuring magnetic conductor 2, a source of alternating voltage 3, the excitation winding 4, the first winding 5 and the second winding 6 are wound on the supply magnetic conductor, the signal winding 7 is wound on the measuring magnetic conductor, the first winding 8 and the second winding 9, the capacitor 10, the amplifier 11 with a single 4HijiM gain, the phase meter 12, the first windings 5 and 8 and the capacitor 10 are connected in series, the second windings 6 and 9 are connected in series and connected opposite with the excitation winding 4, the output of their connection with the excitation winding is connected to the output of the amplifier 11, the second output of the excitation winding is connected to the inverting input of the amplifier 11 and to the output of the alternating voltage source 3, the second output of the serially connected second windings 6 and 9 is connected to the non-inverting input of the amplifier 11, the signal winding 7 is connected to the input of the phase meter 12, which is controlled from the alternating voltage source 3, the electrolyte under study covers the magnetic cores 1 and 2 with a short-closed coil 13,

The device works as follows.

From the alternating voltage source 3, a sinusoidal voltage is applied to the excitation winding 4, which induces a current in the electrolyte. The magnitude of the current in the short-circuited coil 13 of the fluid will be determined by the electrical conductivity of the fluid:

x

Ur w

and

W,

- voltage source 3 AC voltage J

- the number of turns of the winding 6 buzhi;

-conductance of fluid

WHO-

Nom windings 5 and 8 and a capacitor 10, a current will flow

Urw

to

6 1 ° C

 Jw

ULlWjil.C W.

where w ,, cj

the number of turns of the winding 5, the frequency of the voltage of the source 3 of the alternating voltage, C is the capacitance of the capacitor 10. The current IJ, flowing through the capacitor 10 in the input circuit, is shifted by 90 relative to the excitation voltage and the current in the liquid coil.

The magnetic flux in magnetic circuit 2 is defined by

f I bSii..o.yLWM.cw.,.

1m ,

where | jj

(

SM

magnetic permeability of the core material, 4 GN / m,

the cross-sectional area of the toroidal magnetic circuit, tf is the length of the magnetic circuit, the number of turns of the winding 8, by means of the voltage, can be determined from the measuring winding 7:

ii T7 UL uA fUjSM /. „Aptt tt Ui, Wuj-- (jUX-U CWj ,, Wj,),

where Wy is the number of turns of the winding 7.

Representing the voltage Uy in a complex form, we determine the transfer voltage of the excitation voltage to the measuring voltage Uy:

K-HiL WugJifoSM 2, 2С2у

W2 X

kch xi

X e

jarcij

COCVvlK, VJKl

50

Thus, the magnitude of the phase shift between the excitation voltage and the measuring voltage is determined by the expression

Wed arcctg

WCW ,, WK

55

A change in the phase shift tf makes it possible to unambiguously determine the electrical conductivity of the liquid under study. Phase measurement is used to measure the phase.

meter 12, to one input of which a measuring voltage is applied, and to the other - an excitation voltage.

In order to maintain with high accuracy the EMF created in the electrolyte coil by the excitation winding 4, the system introduced the following negative feedback using successively connected windings 6 and 9. The emf induced in the coil 13 of the liquid is determined by the sum of the magnetic fluxes of the magnetic cores 1 and 2, With the help of windings 6 and 9, the total value of the emf induced in the electrolyte by both magnetic conductors is determined. This value of the electromotive force is compared to the excitation voltage on the winding 4 and the difference is fed to the amplitude 11 with a unit coefficient m gain. The differential voltage at the output of the amplifier 11 maintains a constant value of the emf induced in the electrolyte, which is determined with great accuracy by the excitation voltage. The following negative feedback maintains with high precision the constancy of the sum of the magnetic fluxes of the magnetic cores 1 and 2.

Claims (1)

Invention Formula A device for measuring the electrical conductivity of a liquid, comprising a transformer sensor consisting of a toroidal supply and measuring magnetic circuits, Compiled by N.Krinov Editor A.Rezin Tehred L.Serdyukova Order 1628/45 Circulation 731 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and printing company, Uzhgorod, st. Project, 4 O - 0 five five 0 five coaxially placed on each other, the excitation winding is wound on the supply magnetic core, the coil signal C is wound on the measuring magnetic conductor, a source of alternating voltage, one of the excitation windings connected to the output of the alternating voltage source, the signal winding connected to one phase meter input, the other input of which Connected to the output of an alternating voltage source, characterized in that, in order to improve the accuracy of measuring the electrical conductivity of the fluid, the first and second windings are inserted into it oh the magnetic core, capacitor, amplifier with a unit gain, the first windings of the supply and measuring magnetic circuits and the capacitor are connected in series, the second windings of the supply and measuring magnetic conductors are connected in series and connected oppositely with the excitation winding, the output of their connection with the excitation winding is connected to the output of the amplifier with a single gain, the second step of the excitation winding is connected to the inverting input of the amplifier with a unit gain The second output of the serially connected second windings is connected to the non-inverting input of the amplifier with a unit gain factor. Proofreader, M. Demchik