Patent ID: 6159293
Filing Date: 2000-12-12
Classification: C23C

Abstract:
A system for hot dip coating a steel strip, said system comprising:an elongated, trough-shaped vessel for holding a bath of molten coating metal;said vessel having a pair of opposed side walls extending in the longitudinal direction of said vessel and a pair of opposed end walls;said vessel having a relatively wide upper part and a relatively narrow lower part;said side walls converging in a downward direction toward said lower part;said vessel having an elongated opening at the bottom of said lower part;means for moving a steel strip along a path extending in a downstream direction through said bottom opening and through said bath;and an electromagnet disposed alongside said vessel and comprising means for preventing the escape through said opening of the bulk of the molten metal from said bath;said electromagnet comprising a pair of opposed pole members each composed of magnetic material and each disposed along a respective side wall of said vessel;said pole members having opposed, mutually facing pole faces;each of said pole faces being disposed adjacent a respective side wall of the vessel in close substantially abutting relation with that side wall at the vessel's lower part and at that part of said side wall that converges toward the other side wall;each of said pole faces having a contour which substantially follows the contour of the adjacent side wall along that part of said side wall that converges toward the other side wall and along the vessel's lower part;said electromagnet further comprising means for agitating said bath and means for damping the agitation produced by said electromagnet, wherein said damping means comprises:a plurality of substantially parallel pairs of planar members;said pairs of planar members being spaced apart vertically along the path of said strip and extending across said bath in a direction transverse to the direction of the strip path;each of said pairs of planar members defining a slot therebetween;said slots being aligned with the slot defined by each of the other pairs of planar members, to permit the passage of said strip through said slots as the strip moves along its path.