SU1354089A1 - Device for measuring electric conduction - Google Patents

Abstract

The invention relates to a measurement technique, is intended to measure the electrical conductivity of liquids, and may find application in the study of electrolyte solutions in industrial conductometry. The goal is to increase measurement accuracy. The device contains two toroidal magnet wires with windings, a generator connected to the field winding, and a recording device connected to the measuring winding. An amplifier and a phase shifter are additionally inserted into the device, and an additional winding is connected to the magnetic core with the measuring winding connected to the output of the phase shifter, with the amplifier input connected to the measuring winding in parallel with the recording instrument. 1 il. i (l oo ate jiib o 00 with

Description

one

The invention relates to a measurement technique and is intended to measure the electrical conductivity of liquid media.

The purpose of the invention is to increase the accuracy by eliminating the influence of the parameters of the magnetic circuit and the measuring winding on the measurement result.

The drawing shows a diagram of the proposed device.

A device for measuring electrical conductivity consists of an electrical conductivity sensor, which contains a driver magnetic circuit 1 with excitation winding 2 and a measuring magnetic circuit 3 with measuring 4 and an additional 5 windings, an alternating voltage generator 6, an amplifier 7, a phase shifter 8, a measuring and recording device 9 and voltage to current converter 10.

The device works as follows.

The voltage from the generator 6 is applied to the excitation winding 2 and causes the appearance of an alternating magnetic flux in the magnetic circuit 1, which in turn induces an emf in the electrolyte coil. At the same time through the sensor channel flows a current proportional to the conductivity of the electrolyte. In the measuring magnetic core 3, a magnetic flux is induced causing an emf in the measuring winding 4. This signal is amplified and fed to the input of a phase-shifting device providing a 90 ° phase shift

side lag. Subsequently, the signal is converted to current by converter 10 and fed to an additional winding 5. The magnetic flux created by the current in the additional winding 5 is directed opposite to the magnetic flux created by the current in the electrolyte. The amplifier 7, the phase shifter 8, the converter 10 and the additional winding 5 form a negative feedback circuit for magnetic flux. If the feedback loop gain factor, which includes the product of the conversion factors of devices 7, 8, and 10, goes to infinity, the magnetic flux in the measuring core 3 tends to zero.

In this way, current transformer modes at the measuring

Where

magnetic conductor. In this case, the current in the additional winding 5 is equal to the current in the electrolyte divided by the number of turns of the additional winding

I i w /

The amount of loading measured by the device 9 at the output of the amplifier 7 is equal to

and.

   ll

and K.

WsKgK ,, is the conversion factor for phase shifting device and voltage to current converter.

Where

The measured voltage is proportional to the conductivity of the electrolyte and does not depend on the parameters of the measuring magnetic core 3 and the active resistances of the windings 4 and 5.

The proposed device, due to the use of a contactless measurement circuit, does not have such disadvantages as polarization of the electrodes, contamination of the working surface of the electrodes, a change in the contact area between the electrodes and the solution, etc. This provides higher accuracy compared to the base object. In addition, due to the absence of direct contact with the electrolyte, the proposed device has a wider field of application, for example, in measurements in chemically aggressive environments where the use of electrode cells is unjustified.

the invention

formula

A device for measuring electrical conductivity, containing two toroidal magnetic cores, one of which has an excitation winding, the other has a measuring and compensation winding, an alternating voltage generator, a measuring and recording device, and a measuring one. an amplifier covered by negative feedback through the compensation winding, the alternating voltage generator being loaded on the excitation winding, the measuring winding is connected to the input of the measuring amplifier, and the measuring-registering device is connected to the output of the measuring amplifier, which is exactly

 1354089

In addition to the measurement, it is additionally connected with a phase shifter and a converter in series with a voltage to current, the output of which is connected to the compensation winding to the output of the measuring amplifier.

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Editor I.Gorn

Compiled by Yu.Gridnev

Tehred I.Popovich Proofreader V. But ha

Order 5686/38 Circulation 776 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

Claims (1)

40 claims A device for measuring electrical conductivity, containing two toroidal magnetic cores, on one ¢ 5 of which a field winding is wound, on the other - measuring and compensation windings, an alternating voltage generator, a measuring and recording device, a measuring amplifier covered by negative feedback through a compensation winding, and the generator AC voltage is loaded on the field winding, the measuring winding is connected to the input of the measuring amplifier, and the measuring register ruyuschy device connected to the output of the measuring amplifier, characterized i in that, in order to increase the measurement toch1354089 NOSTA, it is additionally provided series connected to the output of the measuring amplifier and phase shifter converter for conjugation to the current, and the latter is connected with the output winding compensation