PROCEDURE FOR CALIBRATING A SENSOR, AUTOMATED METHOD FOR ONLINE MONITORING OF THE CHANGES TO A LIQUID BODY AND ASSOCIATED SENSOR

摘要

A sensor for determining the overall content of a predetermined chemical element in a liquid body uses X-ray fluorescence technology and comprises an X-ray source, an X-ray detector and a cell intended to contain a sample of lubricant to be analysed, and is provided with a wall forming a window for passage of X-rays. The cell also includes a casing defining an internal volume for receiving the sample. The procedure for calibrating the sensor comprises at least the following steps consisting of: establishing (100) a first secondary x-ray spectrum (S1) comprising energy levels (E₁, E₂, E₃, E₄) corresponding to the components of the material of the casing; operating (300) the sensor while the internal volume of the casing does not contain a sample of the liquid body and establishing a second secondary X-ray spectrum (S2); modifying (400) the second spectrum (S2) by using the first spectrum (S1) as a base spectrum for aligning the notable energy levels (E'₁, E'₂, E'₃, E'₄) of the second spectrum on those of the first spectrum and recording (500) the modified second spectrum as reference spectrum (S2') for the sensor. The automated method for online monitoring comprises the prior implementation of the calibration method of the sensor, as well as at least one series of steps consisting of determining, using the prior calibrated sensor, the content of a predetermined chemical element of a sample of the liquid body present or circulating in the internal volume of the casing. The wall of the sensor cell is produced from polyethylene terephthalate.