SU1383263A1 - Device for measuring electric conductivity of liquid media - Google Patents

Abstract

The invention relates to the field of analytical technology, namely, to means of measuring the conductivity of liquid media by conductometric methods, and can be used to solve a wide class of problems of controlling the composition and properties of liquids in the chemical, metallurgical, food and other industries. The aim of the invention is to improve the measurement accuracy. The device also contains a container for the test liquid divided into two volumes by a dielectric partition. Electrodes are installed in each volume. Volumes are connected by a calibrated channel, made in the dielectric partition. The device is equipped with a removable dielectric insert having a hole that is coaxial and coincident in pro-g file with a calibrated channel of the partition. One of the electrodes is made to move to align the geometry of the volumes. 1 il.

Description

The invention relates to measuring instrumentation, relates to measuring the conductivity of liquids by a contact conductometric method for determining the composition and dissolution properties of them in a large number of materials, can be widely used to control the composition and properties of liquid substances and processing processes in chemical, metallurgical, food and other industrial areas

The purpose of the invention is to increase the measurement accuracy.

The drawing shows a functional diagram of the device.

The device contains electrodes 1 and 2, a dielectric septum 3 (calibrated connecting channel, conductometer 4, additional removable dielectric insert 5 dividing the capacitance for the test liquid into volumes 6 and 7. The electrode 2 is made moving. The dielectric insert is equipped with an orifice coaxially and coinciding along the profile with the connecting channel of the partition 3. At least one of the electrodes (electrode 2) is installed in the vessel with the possibility of its movement along the O.SI of the connecting channel.

The device works as follows

Volumes 6 and 7 with the installed dielectric septum 3 are filled with the test liquid. The resistance between the electrodes 1 and 2 is measured using a conductometer 4. Then the calibration channel length and the distance between the electrodes are simultaneously increased. To do this close to the dielectric partition 3, the dielectric insert 5 is set and the electrode 2 is moved to the width of the insert 5, leaving the volume 7 unchanged , The resistance between the electrodes is measured and, based on the results of joint measurements, the electrical conductivity is determined for the liquid under study: b

%

SK (Z

hp.

-Z

kn,

)

(one)

- width dielectric

insert 5;

- cross-sectional area of the calibrated channel; 55 result of the first measurement

resistance;

 the result of the second measurement of resistance.

When located between the electrodes 1 and 2 of the conductometer 4 of the dielectric partition 3 with a calibrated channel, the measured resistance between the electrodes 1 and 2 is formed from the sum of the resistances of the transition electrode 1 - solution Z ,, solution volume between electrode 1 and the partition 3 RQ, solution volume in a calibrated channel septum 3 kc, the volume of the solution between the septum 3 and the 2 Rp electrode and the solution-electrode 2 Z junction, which is expressed by the equation

five

0 0

5 0 5

0

five

ZK, Zn. + Rp, + R .. + RP, + z,

(2)

, -. ,, PI, When increasing the length of the calibrated channel to the width of the additional insert 5 with the calibrated channel, which is installed closely with the partition 3 with the calibrated channel, the resistance between the electrodes 1 and 2 increases by the size of the solution volume in the calibrated channel of the additional insert 5 Кк2 while reducing it by the resistance value

The volume of the solution, by which the volume of the solution between the electrode 2 and the insert 5 with the calibrated channel, becomes less than the volume of the solution between the electrode 1 and the partition 3 with the calibrated channel. However, when the electrode 2 is moved across the width of the dielectric insert 5 with a calibrated channel, the resistance of the solution between the insert 5 and electrode 2 increases to the resistance value Rpj. Therefore, while simultaneously increasing the length of the calibrated channel and moving the elec- type 2 from the surface of the dielectric septum 3 with a calibrated channel for the width of the insert 5 with a calibrated channel, the measured resistance between the electrodes 1 and 2 is determined by the equation

Z ,, Z ,, + Rp, + R ,, + R ,. (3)

Therefore, the measured resistive. Z suppression between electrodes 1 and. 2 after simultaneously increasing the length of the calibrated channel and the distance between the electrodes 1 and 2 by the width of the insert 5 with the calibrated channel differs (more) from the measured resistance Zк „between the electrodes 1 and 2 by the amount of resistance of the solution volume in the calibrated channel of the insert 5 R whose value The difference between the measured resistances Zn and between the electrodes 1 and 2 depends on the cross section S, and length 1 ,. the calibrated channel of the insert 5, as well as the electrical conductivity of the solution%, which is expressed by the equation

Z

kn,

-g „

 SK-

(four)

Relation (1) follows directly from the joint measurement equation (3).

The device provides a measurement of the electrical conductivity of liquid media with an error of no more than 0.2%.

Claims (1)

Invention Formula A device for measuring the electrical conductivity of liquid media, containing a conductivity meter with two electrodes, which are located in the tank for the test liquid and are separated by a dielectric septum with a calibrated connecting channel, characterized in that it is equipped with at least removable additional dielectric insert with a hole coaxially and coincident along the profile with the connecting channel, and at least one of the electrodes is installed in the vessel with the possibility of its displacement along the axis of the connecting channel, 3 5 L DG / .