(57) Process for the anodic oxidation of the metals, in particular of aluminium and its
alloys, consisting in making a metal plate or strip (17) advance, by a conveyor means,
through a plurality of electrolytic cells, containing the same anodizing bath, and
positioned in a sequential approached arrangement; each cell is provided with an electrode
(13, 14, 15, 16 etc.) having alternatingly opposite polarity relatively to the polarity
of the electrodes of the adjacent cells, so as to create oxidating anodic cells alternated
to reducing cathodic cells, able to cause the formation on the metal plate of an oxide
layer having increasing thickness, as the plate is conveyed through the sequential
oxidating cells; and then in extracting, from the last cell, which is preferably an
oxidating cell, the plate thus anodized.
An equipment having the purpose of accomplishing such a process, in which an endless
belt conveyor (1), taut between end rollers (2, 3), on which a plurality of rollers
(6, 6a, 6b, 6c), positioned equally spaced from each other, and closed at their ends
by staunch containment side walls, are mounted, each adjacent couple of said rollers
(6-6a; 6a-6b) constituting, together with its respective side walls (7, 8), a cell,
under each of which cells a plate to be anodized being advanced; to each cell an
electrode (13, 14, 15, 16 etc.) is associated, alternatingly having opposite polarity
relatively to the polarity of the electrodes of adjacent cells, all the cells being
fed with the same anodizing bath, said plurality of adjacent cells defining oxidating
anodic chambers alternated to reducing chatodic chambers, able to form a layer of
oxide by sequential steps of anodic oxidation. Furthermore, means for the recovery
of the solution leakages, as well as means for the recycle to the individual cells
of said leaked solution are provided.
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