METHOD FOR DETERMINING THE SURFACE TENSION COEFFICIENT OF A LIQUID BY COMPARATIVE ANALYSIS Russian patent published in 2021 - IPC G01N13/02 

FIELD: physics; measuring.

SUBSTANCE: invention relates to the field of surface phenomena in a liquid; it can be used in measuring technology to determine the surface tension coefficient of the test liquid by comparative analysis with the surface tension coefficient of a reference liquid similar in chemical composition. In order to determine the surface tension coefficient of the liquid by comparative analysis, drop 14 of reference liquid 10 and drop 15 of chemically similar test liquid 11 with spherical surfaces are formed on horizontal upper section 13 of capillaries 4. To do this, an excess pressure P_Ex of the gas is supplied to vessel 1 with reference liquid 10 and to vessel 2 with test liquid 11 through side taps 5 using a microcompressor 6. The value of the excess pressure P_Ex of the gas is controlled during the supply to vessel 1 with reference liquid 10 and to vessel 2 with test liquid 11 using precise adjustment valves with pressure gauges 7. The excess controlled pressure P_Ex of the gas affects the surface layer of reference liquid 10 and test liquid 11, making them rise along vertically inserted capillaries 4 to form drops 14 and 15 with spherical surfaces on horizontal upper section 13 of capillaries 4. At the time of formation of drop 14 of reference liquid 10 with a spherical surface on horizontal upper section 13 of capillary 4, the excess pressure P_ExRef of the gas is measured using pressure gauge of precise adjustment valve 7, valve 7 is closed and the gas supply to vessel 1 is stopped. Having established in vessel 2 with test liquid 11 using pressure gauge of precise adjustment valve 8 the value of the excess pressure P_ExTest of the gas, corresponding to the value of the excess pressure P_ExRef of the gas in vessel 1, valve 8 is closed and the gas supply to vessel 2 is stopped. Using video monitoring tool 9, the height a_Ref of formed drop 14 of reference liquid 10 and the height a_Test of drop 15 of test liquid 11 with spherical surfaces are measured over horizontal upper section 13 of capillaries 4 to determine the height difference b of formed drop 14 of reference liquid 10 and drop 15 of test liquid 11. Using the difference b between the measured heights a of the formed drops of the reference and test liquid, the value of the surface tension coefficient σ_Test of the drop of the test liquid is determined by comparative analysis with the value of the surface tension coefficient σ_Ref of the drop of the reference liquid, using the calculation method.

EFFECT: simplification of the procedure for performing a comparative analysis of the surface tension coefficient of the test liquid with the value of the surface tension coefficient of the reference liquid similar in chemical composition, while reducing the time spent on conducting express analysis while maintaining a high degree of accuracy of the results obtained.

1 cl, 3 dwg