Patent ID: 6936307

Claim:
A process for the Continuous dip-coating of a metal strip ( 1 ) in a tank ( 11 ) containing a liquid metal bath ( 12 ), in which process the metal strip ( 1 ) is made to run continuously, in a protective atmosphere, through a duct ( 13 ), the lower part ( 13 a ) of which is immersed in the liquid metal bath ( 12 ) in order to define with the surface of the bath, and inside this duct ( 13 ), a liquid seal ( 14 ), the metal strip ( 1 ) is deflected around a deflector roller placed in the metal bath ( 12 ), and the coated metal strip ( 1 ) is wiped on leaving the metal bath ( 12 ), characterised in that a natural flow of the liquid metal from the surface of the liquid seal ( 14 ) is set up in an overflow compartment ( 25 ) made in the duct and having an internal wall which extends the duct ( 13 ) in its lower part and at least facing that side of the strip ( 1 ) lying on the same side as the deflector roller ( 15 ), an upper edge ( 21 ) of the compartment ( 25 ) is positioned below the surface, the drop in height of the liquid metal in this compartment ( 25 ) is maintained greater than 50 mm in order to prevent metal oxide particles and intermetallic compound particles from rising as a countercurrent to the flow of liquid metal, the level of liquid metal in the compartment ( 25 ) is maintained at a level below the surface of the liquid seal ( 14 ), and the duct ( 13 ) is extended, in its lower part ( 13 a ) and facing that side of the strip ( 1 ) lying on the opposite side from the deflector roller ( 15 ), by a second internal wall ( 26 ) directed towards the surface of the liquid seal ( 14 ), the upper edge ( 27 ) of which internal wall ( 26 ) is positioned above said surface and forming a sealed compartment ( 29 ) for storing the metal oxide particles.