Reply to “Comments on 'Role of bubble size for the performance of continuous foam fractionation in stripping mode”'

A commenting letter on a recent publication challenges the measurement technique developed for optically determining bubble size distributions in foams of continuous foam fractionation in stripping mode. The author assumes an effect of bubble distortion at the glass wall leading to a misinterpretation of the experimental results. In this reply letter it will be shown that bubble distortion is of less relevance in the measurement technique considered confirming validity and reliability of the bubble size measurement method developed. Thus, the correlations between the bubble size and the liquid fraction in the foam and the operating conditions as well as the separation performance in the original publication are seen to be valid.