Simultaneous Measurements of Temperature and Moisture Content Profiles of Paper in Drying Process

Abstract

A method of measuring changes not only of the temperature profile, but also of the moisture profile of paper in a drying process is established. Thin electrodes on which is laden high-frequency voltage are inserted between paper sheets, and the impedance between the electrodes is measured in order to evaluate the moisture profile. Also thin thermocouples are inserted between the paper sheets in order to measure the temperature profile. A moist paper to be dried is attached to a hot roll on one side, and a canvas is attached to that on the other side in which hot air flows. The change of temperature profile and that of moisture profile in this drying process are measured at the same time. The temperature of the roll side of the paper increases more rapidly than that of the canvas side and the paper moisture of the roll side decreases more rapidly than that of the canvas side. As a result, it is confirmed that it is necessary to deal with a paper sheet as a porous material to accurately predict its drying process.