| 摘要 |
PURPOSE:To prolong the life of plating kettles and make exchanging of an inner kettle easy by constituting the hot galvanizing kettles by a heat-resisting-steel-made outer kettle and a corrosion-resistant-steel-made inner kettle and using molten Pb as a heating medium between the inner and outer kettles. CONSTITUTION:A corrosion-resistant-steel-made inner kettle 13 is positioned in a heat-resisting-steel-made outer kettle 14 by means of metal fittings 15, 16. Molten Zn 22 is put in the inner kettle 13 and molten Pb 19 is put as a heating medium for inner kettle between the outer kettle 14 and inner kettle 13. The inner kettle 13 is retained by beams 18 at four corners to be prevented from being floated by the buoyancy of the molten Pb 19. Since heating of the moten Zn 22 is accomplished by the molten Pb 19, local heating to a high temperature does not occur. In addition, the outer kettle 14 is in contact with the Pb 19 which does not contain Zn and therefore it will not be attacked by Zn and has a longer service life. Since the outside surface of the inner kettle 13 is also in contact with the Pb 19 which does not contain Zn, it is kept free from erosion through alloying. Easy removability of the inner kettle 13 from the outer kettle 14 makes its exchange extremely simple. |
