SU924561A1 - Method of measuring electrical conductivity of various media - Google Patents

Description

The invention relates to the study of the physicochemical parameters of liquid, bulk and solid media by a conductometric method and can be used to control mechanical stresses in monolithic formations, for scientific research, in the development of instruments controlling technological parameters. changes in their electrical impermeability in the mining, chemical, medical, food, metallurgical, nuclear, construction, and other areas of industry.

Methods are known for determining the physicochemical parameters of liquid, bulk and solid media by a conductometric method based on measuring the current in the sensor circuit {Ij.

However, the methods are characterized by a low measurement accuracy due to the nonlinearity of the output signals and the dependence on changes in the monitored parameters, polarization phenomena, the influence of external factors or measurement circuits, etc .; low stability, noise immunity, especially when measuring media with low conductivity; low resolution t-ability, the influence of parasitic capacitances connecting conductors.

The closest to the present invention is a method for determining the electrical conductivity of liquids (electrolytes) using a conductometric sensor and a pulse generator based on a change in resistance R or an effective value of capacitance C of electrolytic cells included in RC chains determining the frequency modulation of signals generated generator 2.

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The disadvantages of the method are the dependence of the resolution on the use of certain combinations of electrolytic cells with RC circuits, the accuracy of compliance with geometric

20 sizes and distances between electrodes, etc .;

insufficient accuracy of measurements due to the nonlinear dependence of the period of frequency oscillations on the electrical conductivity;

dependence of frequency stability on the type of applied RC-chains.

Claims (2)

The purpose of the invention is to improve the accuracy, resolution and stability of measurements. The goal is achieved by the fact that, in the method of measuring the electrical conductivity of various media using a conductometric sensor and a pulse generator, the sensitive elements of the sensor are placed in the test medium at the required distances or the medium is placed between the sensor elements, the equivalent resistance of the conductometric sensor being investigated medium and convert the change in the specified resistance by the integral frequency defining RC chain into a frequency signal determining the period d oscillator pulses, by which is judged on the electrical conductivity of the medium under study mine. The period of oscillations generated by the generator, with such a switch on sensor and appropriate selection of generator elements, is determined by the linear expression T KES, where Rj and C are the parameters of the frequency-setting integrating chain; Rg is the equivalent resistance of the sensor with the medium being studied; С - capacitor capacitance. The constant current component in the sensor circuit is almost equal to 0, which excludes polarization phenomena and increases the measurement accuracy. Obtaining a linear dependence of the increment of the oscillation period on the electrical conductivity of the medium under study is very significant in devices with direct readings, i.e. T f (), where is the electrical conductivity. The proposed method is characterized by the linear dependence of the frequency output signals of the generator on changes in the physicochemical parameters and, consequently, the electrical conductivity of the studied media, high noise immunity, which is especially important for measuring the physicochemical parameters of media with low electrical conductivity; increases measurement accuracy by 2-3 times. The resolution of the device increases by a factor of 3-5, while increasing the stability of measurements by several times. The proposed method will make it possible to more widely apply the conductometric method of measurement in various areas of national economy, in scientific research in combination with elements of computer technology, and it is possible to carry out geophysical studies of mechanical stresses in natural and artificial. monoliths. The invention The method of measuring the electrical conductivity of various media using a conductometric sensor and a pulse generator, characterized in that, in order to improve the accuracy, resolution and stability of measurements, determine the equivalent resistance of the conductometric sensor with the test medium and convert the change in the specified resistance I by integral the frequency-response chain in the frequency signal, which determines the oscillation period of the pulse generator, according to which the court T about electrical conductivity n. Sources of information taken into account in the examination 1, USSR Copyright Certificate 648833, cl. G 01 N 27/06, 1979. 2. Lopatin V.A. Conductometry. Novosibirsk Publishing House of the Siberian Branch of the Academy of Sciences of the USSR, 1964, p. 136-138, fig. 6, 22-6,24 (prototype).