Dyeing process control algorithms

Nobbs et al continued work on optimising the dyeing process as a whole, including control of other variables such as flow rate, flow reversal and controlled addition of dyes and auxiliaries." This approach required the control algorithms to be extremely flexible, and to react to the current situation rather than simply following a pre-set cycle. 

Key words control algorithms, discontinuous control modes, continuous control modes, composite control modes, analog and digital processing, pH measurement and control, dyeing control. 

The effects of the addition of salt, concentration of dye and the dyebath temperature may also be considered in the design of the pH control algorithm. If the desired pH at any given cycle is not achieved, the next cycle s pH value should compensate for this shortcoming. A simple flowchart of this process is given in Fig. 7.26. 

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