| 摘要 |
When hot dip coating a substrate with metal a blanket of non-reactive vaporised liquefied gas is created over the surface of molten metal in which the substrate is dipped so as to prevent or reduce oxidation of the molten metal. Liquid nitrogen is sprayed from nozzles 14 of a spray header 12 along or at the surface of the molten metal 6. The liquid nitrogen vaporises, and the so-formed vapour is drawn across the surface of the molten metal, providing an 'inert' blanket of gas thereacross, by means of a fan 22. The vapour is collected in a hood 16 on the side of the tank 2 opposite the nozzles 14. Steel may be hot dip coated with Zn, Al or Sn. <IMAGE> |
