SU868517A1 - Four-electrode conductometric cell - Google Patents

Description

(54) FOUR-ELECTRODE CONDUCTOMETRIC CELL

Claims (2)

The invention relates to electrical measuring equipment and can be used to measure the conductivity of liquid media. A known conductometric cell for measuring the electrical conductivity of liquid media containing current electrodes to which a measuring and potential current is supplied, and potential electrodes located between the current and serving to measure the voltage drop from the measuring current, which is proportional to the electrical conductivity of the medium til. The drawback of the device is the presence of a number of measurement error sources limiting the measurement accuracy: the flow of measuring current outside the cell, the influence of the shape and dimensions of the cell, the influence of the shape, size and relative position of the electrodes, heating, electrical location of the medium, etc. The closest in technical terms to the present invention is a conductometric cell containing two flat current electrodes, to which a constant measuring current is supplied, and two flat potential electrodes, located between the current ones and those used for measurement. voltage drop from measuring current. To increase the measurement accuracy by reducing the flow of the measuring current through the volume of fluid, the device is placed in a separate chamber in communication with the volume of fluid. The presence of the camera limits the spreading of the measuring current. increase measurement accuracy by reducing the flow of the measuring current outside the cell chamber through the holes connecting this chamber with the volume of liquid; the device includes an additional electrode located behind the current electrode (from the hole side), which is at an appropriate potential, which reduces the passage of the measuring current outside cell 2}. The disadvantage of this device is limiting the measurement accuracy due to the insufficient efficiency of the additional electrode, which does not completely prevent the measurement current from flowing outside the cell, as well as limiting the measurement accuracy due to the influence of the size, configuration, and location of the potential electrodes in the cell, potential depends on the degree of removal of potential electrodes from the cell wall of the cell, as well as in connection with the fact that each of the potential electrodes is not ie on the surface of any one equipotential. The purpose of the invention is to improve the accuracy of measuring the electrical conductivity of liquid media by preventing the measurement current from flowing outside the cell, limited by the internal area between the current electrodes, and also by reducing the influence on the accuracy of measuring the dimensions, shape and location of potential electrodes in the cell. that in a conductometric cell containing two current and two potential electrodes located between current electrodes, electrodes for transmission of measured current is formed in a reticulated concentric spheres. The potential electrodes used to measure the voltage drop from the measuring current are made in the form of net concentric spheres, located between the current electrodes and having a common center with the latter. In the cell, all the measuring current nmivm does not extend beyond the external current electrode limiting cell volume, and performance of potential electrodes in de concentric spheres eliminates their influence. dimensions, shape and location inside the cell, accuracy of measurements, as it provides a change in voltage drop from the total measuring current flowing between the external and internal current electrodes and the combined configurations of electrodes with electric potentials introduced by the measuring current at the locations of the potential electrodes. The drawing shows the proposed cell. The cell includes external current 1 internal current 2 electrodes, potential external 3 and internal potential 4 electrodes, as well as insulated conductors 5 and 6. Between external 1 and internal 2 current grid spherical electrons. The genera that have a common center and serve to pass a measuring current have potential spherical mesh electrodes 3 and 4, which have a common center with current electrodes and serve to measure the fall of the voltage. from measuring current compensation method. The measuring current is supplied to the current electrodes using insulated conductors 5, and the voltage drop from the potential electrodes is removed using insulated conductors 6. All spherical electrodes can be assembled from individual elements, such as hemispheres. The distance between the individual electrodes is rigidly fixed. The cell works as follows. The cell is placed in a liquid whose conductivity is to be measured. A fixed measuring current is passed between the current electrodes and the voltage drop from the measurement flux between the potential electrodes is measured by a compensation method. The measured voltage drop at a fixed measuring current nponoj) is the electrical conductivity of the medium. The calibration of the device is carried out using a fluid with known electrical conductivity. The proposed cell allows accurate measurements in the technique by measuring the salinity of liquids in tanks of various configurations and volumes, as well as pipelines, and in physical and chemical analysis by conductometric titration of turbid or. highly colored solutions. To ensure measurement accuracy, the cell does not require special chambers and the stationary design of the device and the measurements can be carried out immediately after the cell is immersed in a controlled fluid. Claim 1. A four-electrode conductometric cell containing two current and two potential electrodes located between the current electrodes, which is characterized by the fact that, in order to improve the measurement accuracy, the current electrodes are made in the form of mesh concentric spheres 2. Cell different from so that potential electrodes are made yen in the form of reticular concentric spheres having a common center with current electrodes. 665176 Sources of information taken into account when eksperggyee 1.Musakin A.P., Rachinsky F.Y., Suglobova KD, Reference book, Equipment for chemical laboratories. L., Chem 1978. p. 281. 2. For the UK № 133О295, cl. (ch 01 R 27 / 24,1967 (prototype).