Closed-loop control circuit with electrically powered, heat-radiating correcting device for the transverse profile correction of webs of material, in particular webs of paper, cardboard, fabric or plastic

摘要

An installation for producing and/or upgrading a running web of material, in particular a web of paper, cardboard, fabric or plastic, is equipped with one or more roll presses for dewatering or calibrating and/or smoothing the running web of material on the principle of web compression. In this installation there is also installed at least one closed-loop control circuit which comprises not only measured-value pick-ups, preferably traversing, and a computer and control-pulse generator unit, as main components, but also, as a further main component, an electrically powered, heat-radiating correcting device for correction of the transverse profile of the running web of material. This electrically powered, heat-radiating correcting device functionally comprises individual heating elements which act as thermal radiators, are subdivided into zones over the width of the web of material and are directed with varying intensity at one or more metal rolls of the roll press(es) and, as a result, a correction of the transverse profile of the running web of material is brought about by varyingly intense compression of the web of material. The latter is a consequence of zonally varied diameter of the metal roll(s) by heating caused by heat transmitted by thermal radiation.