The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 14, 1990
Filed:
Apr. 13, 1989
Jyrki Jaakkola, Korpilahti, FI;
Valmet Paper Machinery Inc., , FI;
Abstract
Method and arrangement in a machine for the manufacture of paper or board, for heating an outer face of a cylinder or roll which is in direct contact with a web to be pressed thereagainst. The cylinder or roll face is heated from outside inductively by using a magnetic field, and by which a heating effect based on eddy currents is produced in the outer layer of the roll or cylinder. A relatively thin outer layer of an electrically conductive ceramic material is used as the cylinder or roll face, in which the resistive heating effect is concentrated. The depth of penetration of the heating effect in the radial direction of the roll of cylinder to be heated is restricted to a sufficiently low depth by choosing the thickness of the ceramic outer layer and/or the electric frequency of the induction heating. Additionally, on the basis of its electrical properties, the ceramic material of the outer layer is chosen so that the cylinder or roll face is provided with the necessary properties of strength, and is also chosen in view of the thermal shock of the heating effect.