Patent ID: 7865314

Claim:
A method of determining the salinity of liquids by standard calibrated measurements of the electrical conductivity of a heated liquid sample in a measuring cell, comprising the steps of: providing the measuring cell in a constantly cooled and mechanically stirred as well as heatable water bath insulated to the exterior under control parametric consideration of the thermal conditions in the water bath; measuring with a thermometer the actual temperature (Î¸ B ) as an equivalent of the temperature (Î¸ P ) of the sample at a high repetitive accuracy and with a maximum permissible lag error (Î”Î¸ max ) between the temperature of the water bath and sample temperature (Î¸ B , Î¸ P ) set by the required accuracy of determining the salinity (S), a control parameter for taking into account the thermal conditions being the time-wise drift (Î±=Î”Î¸ B /t) of the temperature (Î¸ B ) derivable from the temperature measurements, the permissible maximum value (Î± max ) of which is defined as the quotient (Î± max =Î”Î¸ max /Ï„) of the maximum permissible lag error (Î”Î¸ max ) and a time constant (Ï„) of the measuring cell (MC) for a temperature equalization between the interior of the measuring cell and the water bath (WB), and controlling with a control device the permissible maximum value of the time-wise drift (Î± max ) of the temperature (Î¸ B ) of the water bath by maintaining a low-lag and quickly controllable compensation of the heat currents (PÂ±) flowing into and out of the water bath (WB) such that the resulting quantity of the residual heat current (P rest ) does not exceed a predetermined maximum value (P restmax ).