SU1635103A1 - Oscillator-based transducer for remote conductivity measurements - Google Patents

Description

one

(21) 4604003/25

(22) 11/09/83

(46) 03/15/91. Bul Number 10

(71) Kuibyshev Polytechnic Institute. V.V. Kuybysheva

(72) C. J. Cooper, S. A. Nechaev, M G. Rubtsov E. I. Tatarenko and V. D. Smirnov (53) 543.25 (088.8)

(56) The principle of the construction of technical means of exploring the ocean. / Under the editorship of V.S. Yastrebov. M; Science, 1982, p. 39 40

USSR author's certificate M; 1492259, class G 01 N 27/02 26 01 87

(54) AUTOGENERATORAL TRANSFORMER WATER REMOTE CONDUCTIVE METER

(57) The invention relates to conductometry and can be used for remote measurement of the concentration of electrolyte solutions, in particular, sea water. Purpose and justification - improving the accuracy of a self-generating converter of a remote conductivity meter. The auto-generator converter contains a comparison unit, a two-pole voltage regulator, a current source, a capacitor, a four-electrode conductivity cell, a three voltage follower and a resistor, with the input of a two-voltage voltage regulator connected to the voltage output. unit of comparison, and the output with the input of the current source, one potential electrode of the cell is connected to the input of the first repeater voltage and the code connected to the second input of a two-pole voltage regulator, the vuro and potential electrode is connected to the inverting input of the clutter unit whose non-inverting input is connected to the output of the two-voltage voltage regulator. The RHPD of the second repeater is connected to the output of the current source and one of the capacitor covers and its output with a resistor lead whose second output is connected to the input of the third repeater whose output is connected to the second capacitor plate and the first current electrode of the conductor cell of the second current electrode of which is connected to bus circuit The invention allows to improve the accuracy of measurements of conductivity in remote measurements by using a four-electrode cell and transmitting information FM signal 1 sludge

sl C

oh so

about

CJ

The invention relates to conductance and can be exploited for day-to-day measurements of the concentration of electrolyte solutions, in particular, sea water.

The purpose of the invention is improving the accuracy of measurements.

The drawing shows the unit with / em of the proposed Converter

The converter contains a four-electrode conductometric cell 1

with two current 2 and 3 and two potential 4 and 5 electrodes unit 6 comparison two-pole voltage regulator 1 voltage source 8 current capacitor 9 resistor 10 and voltage repeaters 11-13 voltage The output of the comparison block b is connected to a two-pole voltage regulator 7 A potential electrode 4 is connected to the second input of which through the voltage follower 11. The output of the two-pole stabilizer 7 ylpr + -nie "is connected to the input

current source 8 and the non-inverting input of the comparator unit 6 and is the output of the converter. The output of the current source 8 is connected to the input of the voltage follower 12 and one of the plates of the capacitor 9. The output of the voltage follower 12 is connected to the output of the resistor 10, the second output of which is connected to the first current electrode 1 2 and the voltage follower 13, and the output of the voltage follower 13 The second current electrode 3 is connected to the common bus of the circuit, and the potential electrode 5 is connected to the inverting input of the comparison unit 6. The converter is connected to the measuring equipment by a two-wire line.

The Converter operates as follows.

When the circuit is turned on and the conductometric cell 1 is immersed in the test medium, at the initial moment at the output of the comparison unit 6, either a positive or a negative voltage U is established, which is stabilized by a two-pole voltage regulator 7, and the voltage at its output relative to the common bus of the circuit equally

UcT ° UcHU40, (1)

where UCT is the stabilization voltage of the two-pole stabilizer 7;

the tension between potential electrode 4 and the common bus.

Current source 8 provides current. corresponding to the polarity of the voltage from the output of the two-pole voltage regulator 7. The capacitor 9 is charged and its voltage varies according to the expression

Uc, (2)

where I - current source 8 current;

t is the charge time;

С - capacitor capacity 9

Since the voltage on the plates of the capacitor 9 and on the resistor 10 due to the connection of the repeaters 12 and 13 of the voltage are equal, then through it flows a current equal to

| R- | R С R

(3)

where IR is the current through resistor 10;

R is the resistance of the resistor 10.

The same current flows through the conductor: on the cell 1. Thus, the voltage on the potential electrode 5 relative to the common bus will be equal to

USD-- 75 (), (4)

0

where R-15 is the resistance of the section of the test fluid between the electrodes 4 and 5;

R43 - resistance of the test fluid between the electrodes 4 and 3:

Zs is the impedance of the double layer electrode 3.

To the second input of the two-pole voltage regulator 7 through the voltage follower 11, the voltage of the potential electrode 4 is equal to I t

U ™-g (). (5)

The voltage at the output of the two-pole stabilizer 7 relative to the common tire 5, taking into account (1), will be equal to

U st ° Uc

4 SG

(R-13 (Z3), (6)

five

0

As soon as the voltage Uso at the inverting input of the comparison unit (6) becomes 0 step voltage of 1) h ° at the non-inverting input, the output voltage of the comparison unit 6 will change to the opposite and the process will repeat.

Thus, in view of (4) and (G), it follows that

(7)

.-%:

R / I5

If we denote by K the geometric constant of the cell and take into account that the conductivity is 1 / R, then expression (7) takes the form

UCT C R K

t

G

(eight)

where G is the specific conductivity of the liquid under study.

Since the full period of oscillation is determined by the voltage variation from -UCT ° to Ucr ° and back, the full period of oscillation is equal.

The period of the output signal from the converter is

L is

C R K

G

(9)

45

or by designating

BUT -

With R

will get

T A G

From the last expression it follows that the period of the output signal is directly proportional to the conductivity of the liquid and does not depend on the resistances of the capacitances of the double layers of all electrodes and their contamination.

Claims (1)

Claims of the invention A self-generating converter of a remote conductivity meter, comprising a comparison unit, two-gyro stabilization voltage torus whose output is the converter output, current source, capacitor, conductometric cell with two current electrodes, one of which is connected to the common bus of the converter and one potential electrode, the first input of the two-pole voltage stabilizer connected to the output of the comparator, and the output is with a current source input, characterized in that, in order to improve the measurement accuracy, three voltage repeaters and a resistor are introduced into it, and the conductometric cell is made with two current sources two voltage electrodes, wherein one electrode is connected to the potential input 0 the first voltage follower, the output of which is connected to the second input of a two-pole voltage regulator, the second potential electrode is connected to the inverting input of the comparator unit, the non-inverting input of which is connected to the output of the two-pole voltage stabilizer, the input of the second voltage follower is connected to the output of the current source and one of the capacitor plates, and its output - with the first output of the resistor, the second output of which is connected to the first current electrode of the conductometer cell and to the input of the third A repeater whose output is connected to another capacitor plate.