Abstract: A method and apparatus for surface treating metal pipes includes introducing a treatment liquid into a first distribution chamber having a flat bottom surface, and dropping the treatment liquid onto at least a portion of the outer peripheral surface of the metal pipe through a plurality of holes formed in the bottom surface of the first distribution chamber. Preferably, a distance between the bottom surface of the first distribution chamber and the metal pipe is maintained constant as the outer diameter of the pipe varies. The treatment liquid may be introduced into a second distribution chamber having a flat bottom surface, and the treatment liquid may then be introduced into the first distribution chamber through a plurality of holes formed in the bottom surface of the second distribution chamber. It is possible for the first distribution chamber to simultaneously drop the treatment liquid onto at least two metal pipes.

Abstract: Metal pipes (3) are surface-treated by introducing a treatment liquid (2) into a first distribution chamber (11) having a flat bottom surface, and dropping the treatment liquid onto at least a portion of the outer peripheral surface of the metal pipe through a plurality of holes formed in the bottom surface of the first distribution chamber. Preferably, the distance (A) between the bottom surface of the first distribution chamber (11) and the metal pipe (3) is maintained constant as the outer diameter of the pipe varies. The treatment liquid may be introduced into a second distribution chamber having a flat bottom surface, and the treatment liquid may then be introduced into the first distribution chamber through a plurality of holes formed in the bottom surface of the second distribution chamber. It is preferably possible for the first distribution chamber to simultaneously drop the treatment liquid onto at least two metal pipes.