Device for hot dip coating a metal strip
View Patent ↗The invention relates to a device for hot dip coating a metal bar ( 1 ), especially a steel strip, in which the metal bar ( 1 ) is directed vertically through a container ( 3 ) accommodating the molten coating metal ( 2 ) and through a guide channel ( 4 ) mounted upstream thereof. The inventive device comprises at least two inductors ( 5 ) which are arranged on both sides of the metal bar ( 1 ) in the area of the guide channel ( 4 ) and generate an electromagnetic field for retaining the coating metal ( 2 ) inside the container ( 3 ). In order to relax the coating bath, the distance (d) between the walls ( 6 ) that delimit the guide channel ( 4 ) is not kept constant in a direction (N) extending perpendicular to the surface of the metal strip ( 1 ) in the zone (H) of the vertical extension of the guide channel ( 4 ), which is located between the bottom side ( 7 ) thereof and the bottom area ( 8 ) of the container ( 3 ).
1. Device for hot dip coating a metal strand ( 1 ), said device comprising: a coating tank ( 3 ) that contains the molten coating metal ( 2 ) and a guide channel ( 4 ), wherein the guide channel ( 4 ) is arranged upstream, relative to the direction of travel of a metal strand ( 1 ), of the coating tank ( 3 ) such that the strand ( 1 ) is passed vertically through the guide channel ( 4 ) and then through the coating tank ( 3 ), and wherein the guide channel ( 4 ) is comprised of at least two inductors ( 5 ) for inducing an electromagnetic field, which are installed on both sides of the metal strand ( 1 ) in the area of the guide channel ( 4 ) in order to keep the coating metal ( 2 ) in the coating tank ( 3 ), wherein distance (d) between the walls ( 6 ) that bound the guide channel ( 4 ) is not constant in the direction (N) normal to the surface of the metal strand ( 1 ) in the region (H) of the vertical extent of the guide channel ( 4 ) between the lower end ( 7 ) of the guide channel ( 4 ) and the bottom ( 8 ) of the coating tank ( 3 ), such that the walls ( 6 ) that bound the guide channel ( 4 ) have a constriction ( 10 ) or an expansion ( 11 ), wherein at least one flow deflection element for reducing turbulence of the coating metal ( 2 ) therein is arranged in the guide channel ( 4 ).
2. Device in accordance with claim 1 , wherein the cross section of the constriction ( 10 ) or the expansion ( 11 ) has essentially the form of a circular segment.
3. Device in accordance with claim 1 , further comprising at least one additional wherein at least one flow deflection element is arranged in the coating tank ( 3 ) ( 4 ).
4. Device in accordance with claim 3 , wherein the flow deflection element is designed as a flat, narrow plate, whose longitudinal axis ( 14 ) extends in the direction perpendicular to the direction of conveyance (R) of the metal strand ( 1 ) and perpendicular to the direction (N) normal to the surface of the metal strand ( 1 ).
5. Device in accordance with claim 3 , wherein the at least one flow deflection element is arranged in the guide channel ( 4 ) in the region of the expansion ( 11 ).
6. Device in accordance with claim 3 , wherein at least one bath relaxation plate ( 16 ) is arranged in the coating tank ( 3 ) near the surface ( 15 ) of the coating metal ( 2 ).
7. Device in accordance with claim 6 , wherein the position of the bath relaxation plate ( 16 ) can be vertically adjusted by an actuator ( 17 ).
8. Device in accordance with claim 6 , wherein the bath relaxation plate ( 16 ) consists of ceramic material.
9. Device in accordance with claim 8 , wherein the flow deflection element is designed as a flat, narrow plate, whose longitudinal axis ( 14 ) extends in the direction perpendicular to the direction of conveyance (R) of the metal strand ( 1 ) and perpendicular to the direction (N) normal to the surface of the metal strand ( 1 ).
10. Device in accordance with claim 8 , wherein the at least one flow deflection element is are arranged in the guide channel ( 4 ) in the region of the expansion ( 11 ).
11. Device in accordance with claim 1 , wherein at least one bath relaxation plate ( 16 ) is arranged in the coating tank ( 3 ) near the surface ( 15 ) of the coating metal ( 2 ).
12. Device in accordance with claim 11 , wherein the position of the bath relaxation plate ( 16 ) can be vertically adjusted by an actuator ( 17 ).
13. Device in accordance with claim 11 , wherein the bath relaxation plate ( 16 ) consists of ceramic material.