Monitoring the surfactant content is an important step in the quality assurance of coating and cleaning baths. The Bubble Pressure Tensiometer – BPT Mobile used for this purpose now displays the determined concentration directly and without the need for an external reference curve. With this new function, the instrument solves the task of bath monitoring particularly efficiently.
Bubble pressure tensiometers such as the BPT Mobile make it possible to determine the surfactant content using the dynamic surface tension (SFT), which depends on the surfactant concentration. To prepare for quality monitoring, other bubble pressure tensiometers require external software to record a reference curve to determine the exact relationship between concentration and dynamic SFT. The BPT Mobile now takes this step without external help – thanks to the instrument's improved firmware.
To record the internal reference curve, several dynamic measurements, i.e. measurements with variable speed (= surface age) are performed at different concentrations of the surfactant. In this way, not only the concentration dependence of the SFT is recorded, but also the time behavior of the surfactant.
For subsequent bath tests, the Monitoring mode of the instrument uses the stored data from the dynamic measurements to check the surfactant concentration on the basis of a single-point measurement and display it directly. For this purpose, the BPT Mobile also automatically determines the optimum surface age for concentration determination, i.e. the surface age at which the dynamic SFT is most dependent on the concentration.
At parts2clean in Stuttgart (Germany) from 22 to 24 October in Hall 7, Stand D14, we will be demonstrating the internal recording of the reference curve with the BPT Mobile for the first time.