Patent ID: 6895692
Filing Date: 2005-05-24
Classification: C21D,F27B,F27D

Abstract:
1. A device for heat treating metallic webs in-line, in a gas atmosphere, in particular for operation with a low-density protective gas, characterized by the combination of the following features: a) all of the heating and at least the first portion of the cooling is performed in the heat treatment portion, primarily by means of forced convection by blowing said web with impact jets of a heating and/or cooling fluid; b) during said heating and at least in the first portion of said cooling, the web is guided in a non-contact process; c) nozzle fields for generating said impact jets exert a positionally stabilising effect on the web by deploying a planar force onto the web which, similar to a spring, increases with decreasing distance between the web and the nozzle field, the magnitude of said stabilising force depending on the dynamic pressure of the blowing fluid at the nozzle output of the impact jets; d) the distance between the nozzle fields, arranged on both sides of the web in the heat treatment portion, is substantially constant in each of the respective areas, i.e. heating and cooling; e) the web is tensed, due to the effect of gravity, in the treatment area localised by rollers; f) the course of the web between said rollers, which localise the treatment area, exhibits a concave curvature (as viewed from above), at least in a partial area; and g) the position of the web is controlled in the area of the trough of the concave curvature (as viewed in the longitudinal section) by at least one sensor which operates in a non-contact manner.