SU1474533A1 - Device for measuring electric conductivity of fluid media - Google Patents

Abstract

The invention relates to devices for determining the physicochemical parameters of multicomponent liquid media and can be used for scientific research of these media or control of technological processes in various industries. The purpose of the invention is to improve the measurement accuracy by eliminating errors resulting from straightening the signal of a measuring circuit and elimination of the negative effect of polarization phenomena — is achieved by introducing an adjustable source of constant voltage into the known device The power supply, measuring circuit, four electronic key, which are connected according to the scheme of 4-shoulder bridge. At the same time, the electrochemical cell is included in the diagonal of the bridge, the positive output of an adjustable source of direct voltage is connected to the first output of the reference resistor and the positive output of the measuring device, the negative output of which is connected to the second output of the reference resistor, the negative output of the adjustable source a constant voltage is connected to the inputs of the third and fourth electronic switches, the outputs of the first and third electronic switches are connected to The first input of the electrochemical cell and the outputs of the second and fourth electronic keys are connected to the second input of the electrochemical cell, the control inputs of the first and fourth electronic keys are connected to the first output of the alternating voltage generator, and the second anti-phase output of the last electronic keys keys. 1 il.

Description

one

The invention relates to devices for determining the physicochemical parameters of multicomponent liquid media and can be used for scientific research of these media, control of technological processes in agriculture, chemical,

food and other industries.

The purpose of the invention is to improve the measurement accuracy by eliminating errors that occur when the measuring circuit signal is rectified, and

eliminate the negative impact of polarization phenomena.

The drawing shows a block diagram of a device for measuring the electrical conductivity of liquid media.

The device contains an adjustable source of constant voltage 1 whose outputs are connected to the inputs of measuring circuit 2, which includes an electrochemical cell 3 connected to the diagonal of the bridge, and a reference resistor 4, the bridge consists of electronic switches 5-8. The alternating voltage generator 9 is made with the condition of issuing alternating voltage to its outputs in antiphase and is designed to control the operation of the keys in the mode of their pairing locking. Parallel to the resistor 4 is connected to the measuring device 10.

The device works as follows.

From the outputs of the alternating voltage generator 9, the inputs of the keys 5-8 receive signals that control them by pairing (5, 8 and 6, 7) short-circuiting and opening, while the electrodes of the electrochemical cell 3 are alternately connected to the positive and resistor 4 to the negative terminal of the regulated constant voltage source 1 in such a way that the current through the resistor 4 flows in one direction. The frequency of the voltage generated by the generator 9 is chosen such that it excludes the influence of polarization phenomena in the electrochemical cell 3 on the readings of the device 10. The drop in direct voltage on the reference resistor 4, which is proportional to the electrical conductivity of the liquid medium, is measured by the measuring device 10.

The sensitivity of the device is controlled by the change in voltage applied to measuring circuit 2 from a constant voltage source 1.

In this way, it is possible to measure the electrical conductivity of liquid media at a constant voltage, while feeding the electrochemical cell with a variable voltage, which provides an increase in the measurement accuracy.

Claims (1)

U Formula of invention A device for measuring the electrical conductivity of liquid media, comprising an alternating voltage generator, a measuring circuit including an electrochemical cell and a reference resistor, measuring 0 five 0 five 0 five 0 The device, characterized in that, in order to improve the measurement accuracy, an adjustable DC voltage source is supplied to it, supplying the measuring circuit, four electronic switches, which are connected according to the four-shoulder bridge circuit, the electrochemical cell is included in the bridge diagonal, the positive terminal of the adjustable a constant voltage source connected to the first output of the reference resistor and the positive terminal of the measuring device, the negative terminal of which is connected to the second output of the reference resistor a and the inputs of the first and second electronic switches, the negative output of an adjustable source of constant voltage is connected to the inputs of the third and fourth electronic switches, the outputs of the first and third electronic switches are connected to the first input of the electrochemical cell, and the outputs of the second and fourth electronic switches are connected to the second input an electrochemical cell, the control inputs of the first and fourth electronic switches are connected to the first output of the alternating voltage generator, and the second anti-phase output after One is connected to the control inputs of the second and third electronic keys.