The present invention relates to an apparatus for electroplating metallic workpieces such as steel plates with aluminum in a sealed chamber.
The oxide film formed on the surface of aluminum has excellent corrosion resistance. Therefore, aluminum is used for obtaining products having good corrosion resistance and durability.
In general, the aluminum coating is formed on the object by the hot dipping. In the hot dipping method, aluminum is heated at a temperature higher than 600.degree. C. to form a plating bath. Consequently, a large heat source is necessary for providing the plating bath, and other problems arise for performing the aluminum coating.
In recent years, an electroplating has been proposed where the electrolyte is maintained below 200.degree. C. for the aluminum coating. (see Japanese Patent Application Laid-Opens 63-26399, 64-87799, 1-272788 and 1-272790).
The electrolyte solution used in the aluminum electroplating easily reacts with oxygen in the air and water to be deteriorated. Therefore, the electrolyte solution is maintained in a sealed chamber as described in the Japanese Patent Laid Open 63-26399. However, in the prior art, the workpiece is moved in the vertical upward direction, in the horizontal direction, and then in the vertical downward direction, which makes the construction of the electroplating apparatus complicated. Consequently, a high installation cost and troublesome maintenance of the apparatus are imposed. Furthermore, the complicated structure of the apparatus makes it difficult to build a reliable sealing construction.
USPTO Backgrounds
USPTO Backgrounds