CRYOGENIC PAINT STRIPPING AND UNSCREWING PLANTS
Cryogenic separations are based on the ability of cryogenic fluids, such as liquid nitrogen, to reach temperatures low enough to embrittle paint on substrates, making it easier to remove.
Il concetto alla base è semplice: il supporto ricoperto di vernice viene immerso nel fluido criogenico a bassa temperatura, quindi il contatto con il gas liquido fa si che la vernice si contragga improvvisamente, mentre il supporto subisce l’effetto del freddo solo successivamente, con una contrazione meno significativa. As a result, due to the different withdrawal speeds, the paint cracks and separates from the support.
In order to obtain a perfect removal, however, a slight mechanical action is necessary at the end of the operation.
In cryogenic paint stripping systems, the different phases of the operating cycle are automatically carried out:
1) The holder is immersed in a tank filled with cryogenic fluid so that the paint coating becomes brittle and cracks.
2) A shot blasting machine mechanically removes the paint flakes which are then completely detached and collected in special containers, separated from the grit.
3) A water-based release agent is applied to protect the support and simplify the subsequent painting, where necessary
This cryogenic technology represents an ecological alternative to the normal techniques used, such as thermal and chemical paint stripping.