SU1223115A1 - Method and apparatus for measuring parameters of electroconducting medium - Google Patents

Abstract

The invention relates to the field of conductometry and can be used to measure parameters of electrically conductive media in control systems, technological processes and other fields of technology. In order to improve accuracy and informativeness when measuring parameters of electrically conductive media using a three-electrode contact measuring cell, the meter is calibrated when immersed in the medium of the first and second electrodes, while the third electrode is outside the medium, and when measuring all three electrodes are immersed in the medium . In this case, the cell is made in the form of a cone, at the base of which the first electrode is located, and the second and third are made in the form of rings on the surface of a cone, 2 s.p. f-ly, 3 ill. (/) ate

Description

The invention relates to conductometry and can be used in systems for monitoring the parameters of technological processes and other areas of technology where it is required to monitor the parameters of electrically conductive media.

B

The purpose of the invention is to improve the accuracy and informativeness of measuring parameters of electrically conductive media.

FIG. 1 shows a graduation scheme; in fig. 2 - equivalent circuit; in fig. 3 is an electrical circuit of the device implementing the proposed method.

The method of measuring parameters of an electrically conductive medium using a measuring cell with electrodes includes the following working steps

The calibration of the measuring instrument (measuring cell) according to the model solution is combined with the calibration of the device with the aid of a pulsator of electrical conductivity. The measuring cell 1 is immersed in the test medium 2 (for this operation, the sample solution in the dielectric bath 3) to a depth at which the first electrode 4 and the second electrode 5 are immersed, and the third electrode 6 located at the base of the cone 7 of the cell 1 remains in the air. The signal from the pulse shaper 8 is applied to the second 5 and third 6 electrodes, and the conductivity meter 9 is connected to the first 4 and third 6 electrodes. Consistently with the resistivity of the sample solution R.j, the pulsating resistance Rj is turned on. shaper pulsation. By varying the parameters of the sample solution 2, the static component of the resistance (R, 2) is changed by varying the frequency and amplitude of the pulsations — dynamic (Rj.j). Thus, a family of graded curves is obtained. When measuring, cell 1 is immersed completely in the test medium. When this driver 8 pulsations short-circuited by the resistance of the solution.

Device for measuring parameters. a ditch of an electrically conductive medium containing a contact measuring cell 1 in the form of a cone 7 made from a dielectric, at the top of which is located the first

152

electrode 4, and between the top and the base - the second electrode 5, made in the form of a ring on the surface of the cone. The cell is equipped with a third electrode 6 in the form of a ring on the surface of a cone between its base and the second electrode 5. The conductivity meter 9 is connected to the electrode f)

4 and 6, and the calibrator, implemented as a shaper .8 pulsations, to electrodes 5 and 6. Electrode areas

5 and 6 are 100 or more times larger than the area of the electrode 4. The calibrator contains a divider of resistances 10 and 11, made according to a L-shaped scheme, to the input of which is connected a key 12 controlled by a pulse generator 13. Key. 12 short-circuits the resistance 11 and the resistance of the pulsation former varies from R to

10 N

The meter 9 contains a series-connected high-frequency generator 14, a bridge circuit 15, a differential detector of 1 b, an amplifier 17 of direct current and a secondary recording device 18. Electrodes 4 and 6 are connected through one of the bridge arms through a coupling capacitor 19. The circuit 15. The capacitor 19 is selected from the condition of providing capacitance at the operating frequency of generator 14 10-100 times lower than the minimum resistance of the liquid, the output of amplifier 17 through the integrator 20 is connected to the gate of the field-effect transistor 21, the drain and source of which are connected to the electrodes 4 and 5, respectively.

Work meter, is as follows.

Under the action of the voltage generated by the generator 14 on the measuring diagonal of the bridge circuit 15, an alternating voltage appears proportional to the total conductivity of the electrolytic conductor with resistance RX and the field-effect transistor channel 21. This voltage is detected and amplified by blocks

16 and 17 are fed to the inputs of the device 18 and the integrator 20. If the bridge 15 is not balanced, the voltage at the output of the amplifier 17 is not zero, and the voltage at the output of the integrator 20 and the conductivity of the channel of the FET 21 change until the voltage amplitudes at the entrances

differential detector 16 will not be equal to each other. In this case, the voltage at the input of the device 18 is zero. Similarly, the bridge is automatically balanced for any slow changes in fluid conductivity during the measurement process. With fluctuations of conductivity relative to the average value, the conductivity of the channel of the field-effect transistor 21 does not change, since the integrator does not respond to rapid changes in the signal at its input and the device 18 records the fluctuations of the monitored parameter.

Invention Formula

1. A method of measuring parameters of an electrically conductive medium. Using a measuring cell with electrodes, including graduation of a measuring cell according to a sample solution, calibration with the help of a pulsator of electrical conductivity, immersing the cell into the test medium and measuring the electrical conductivity of this medium followed by an assessment based on the results of measuring the parameters of the medium , characterized in that, in order to increase accuracy and

informativity is measured using a three-electrode cell, during calibration the third electrode is placed in air, the signal of the pulsation former is applied to the second and third electrodes, and the electrical conductivity is measured between the first and third electrodes when all three electrodes are immersed.

2. A device for measuring parameters of an electrically conductive medium comprising a contact measuring

A cell made in the form of a cone made of a dielectric, at the top of which is located the first electrode, and between the top and the base of the second, made in the form of a ring on the surface of the cone, an electrical conductivity meter and a calibrator connected to the electrodes, characterized in that accuracy and information content, the cell is equipped

the third electrode, made in the form of a ring mounted on the surface of the cone between the base and the second electrode, the conductivity meter connected to the first and third electrodes, and the calibrator to the second and third.

M-

r / -J

9

Km

Ft 2

FIG. one

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Compiled by N. Stanchuk Editor N. Vobkova Tehred ff.Kadar

Order 1705/46

Circulation 778

VNIIPI USSR State Committee

for inventions and discoveries. 113035, Moscow, Zh-35, Raushsk nab. 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

Proofreader O. Lugova

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Claims (2)

Claim 1. The method of measuring the parameters of the electrically conductive medium _ using a measuring cell with electrodes, including calibration of the measuring cell according to the sample solution, calibration using a ripple shaper of electrical conductivity, immersion of the cell in the test medium and measuring the conductivity of this medium with subsequent evaluation from the results of measurements of the parameters of the medium, different the fact that, in order to increase the accuracy of information content * the measurement is carried out using a three-electrode cell, while calibrating the third the electrode is placed in air, the signal 5 of the ripple generator is applied to the second and third electrodes, and the conductivity of the medium is measured between the first and third electrodes when all three ¹⁰ electrodes are immersed. 2. A device for measuring the parameters of an electrically conductive medium, comprising a contact measuring cell 15 made in the form of a cone made of a dielectric, at the top of which there is a first electrode, and between the top and the base of the second one, made in the form of a ring on the surface of the cone, a conductivity meter and calibrator, connected to the electrodes, characterized in that, in order to improve accuracy and information, the cell is equipped with a 25 third electrode, made in the form of a ring mounted on the surface of the cone between the bases Niemi and the second electrode, wherein the conductivity meter is connected to per30 wave and more third electrodes, and the calibrator - to the second and third. (Riga 1 1-2231 15 * <> fig.Z