Application of thermal barrier coatings to paper machine drying cylinders to prevent paper edge overdrying
AssigneesPulp and Paper Research Institute of Canada, Pyrogenesis Inc.
InventorsNicole A. Poirier, Peter G. Tsantrizos
Life of this patent
Estimating the term…
Abstract
The invention overcomes the problem of paper edge overdrying during the paper drying process on paper machine drying cylinders. It comprises applying a thin ceramic coating onto the circumferential exterior surface of the cylinder near the cylinder edges, thereby forming a thermal barrier coating which decreases paper drying rate at said edges and reduces or eliminates paper edge overdrying.
Claims33
A method of reducing or eliminating paper edge overdrying during a paper drying process on paper machine drying cylinders, which comprises applying a thin ceramic coating onto the circumferential exterior surface of the cylinders only near the cylinder edges, thereby forming a thermal barrier coating at the edges, the thickness of said thermal barrier coating being graded in cross-direction of the cylinder so as to avoid a step change in said thickness and a significant gradient change in temperature across the cylinder, with the graded coating being thickest at outermost edges of the cylinder where overheating is greatest.
A paper machine drying cylinder having a thin ceramic coating on its circumferential outer surface, only near the cylinder edges, said coating being structured and arranged to form a thermal barrier at the cylinder edges, which decreases paper drying rate at said edges and thereby reduces or eliminates paper edge overdrying, the thickness of said ceramic coating being graded in cross-direction of the cylinder so as to avoid a step change in said thickness and a significant gradient change in temperature across the cylinder, with the graded coating being thickest at outermost edges of the cylinder where overheating is greatest.
Dependencies are inferred from the claim text.