Controlling coat weights on hot dip metal coated wires

摘要

#$%^&*AU2010200262B220140821.pdf#####ABSTRACT The disclosed invention is a method and an apparatus for selectively wiping and controlling excess metallic coatings from individual wires through electromagnetic induction and interactions in the contemporary continuous, multi-wire hot dip coating process. For the necessary electromagnetic induction, each coated wire emerging out of a hot dip bath is further passed, without any physical or electrical contact, through a pair of straight, parallel and transversely disposed electrical conductors carrying equal alternating electric currents in opposite directions. The conductors are covered on all outer sides, except those facing the running wire in its vicinity; with substantially Horseshoe or C shaped soft, ferromagnetic cores. Under such conditions, the liquid coating layer entrained on the wire is subjected to electromagnetic induction in the vicinity of the pair of conductors and forces of electromagnetic interactions therein effectively squeeze and wipe away the excess coating layer. The wiped away liquid coating mass returns to the bath under the action of gravity. The coat weight retained on the wire after wiping the excess is further controlled by shielding the electromagnetic induction with electrically conductive shells, as required, while the alternating current in the pair of parallel conductors is stabilized. On a multi-wire manufacturing plant, the conductors for all the coated wires are connected in a series loop circuit and further connected through a series variable inductor or choke to a stabilized electronic power source. In ongoing operations, the inductance of the series inductor is varied in order to maintain the total inductance across the power source and the circuit current constant. The invention covers several practicable arrangements of the pairs of conductors in multi-wire operations on a common hot dip bath and useful shapes and forms of the electrically conductive shells in the manufacturing practice.1 4 WD CT En FF WD 5 N. Fn 37 YB 2o FIG.4