Dye Concentration Calculations Using Derivative Ratio Method in an Online and In Situ Optical Fibre Dyeing Sensing System

The objective of this work was to discuss a calculation method of dye concentration in mixed dye bath, to develop an optical fibre sensing system for in-situ monitoring of dye concentrations in a dye bath and control the rate of exhaustion to ensure that the dyeing process yields the desired product. A designed optical fibre sensing system was proved to be practicable to measure the single dye concentration accurately, it is important to chance right calculation method in measuring mixed dye bath concentration. The experiment prepared known concentration mixture with reactive red 2G and yellow 4G. Based on measured absorption spectra, dyes concentrations were calculated by derivative ratio method. The calculated results were compared with the prepared concentrations. The accuracy was discussed. The results show that calculated dyes concentration by derivative ratio method well matched the prepared value at the certain concentration range.