The hot washing stage serves not only for the removal of adhesives, but also for washing out remaining impurities in the flakes, such as sugar, soda residues, etc, under strict control of the various process parameters such as pH-level, detergent, de-foamer, temperature and dwell time. The complete process, together with the dosing of the caustic agent and detergent are controlled automatically.
By cleaning the process water in an ultra-filtration stage, we can ensure a closed water circuit and reduce the consumption of fresh water, heating energy and chemicals to a minimum. The experience with hot washing in PET washing lines also forms the basis for the modified hot washing steps in film washing lines and PP/PE hard plastic washing lines. With the Herbold hot washing process, qualities of the washed products can be achieved, which in combination with the other washing, separation and drying steps of a Herbold system need fear no comparison with the source materials.