Chemically treating metal surfaces comprises contacting the metal surfaces with a solution of a process bath, in which the solution of the bath is circulated via a first line and a circulating pump

摘要

Chemically treating metal surfaces comprises contacting the metal surfaces with a solution of a process bath (1), in which the solution of the bath is circulated via a first line (2) and a circulating pump (3). Gas is introduced via a second line (6). The outlet opening (11) of the first line lies 50-150 cm below the surface of the process bath. The length of the guiding section of the line lies between a Venturi system (4) and the outlet opening. An Independent claim is also included for a device for chemically treating metal surfaces. Preferred Features: A third line (9) branches from the first line before the Venturi system and introduces a partial stream of the circulating solution of the process bath into the bath. The solution is a phosphating solution.