Residual humidity measurement for moving material web - using screening effect on generated electrical field to determine humidity-dependent DC resistance of web

摘要

The residual humidity measuring method involves generating an electrical field over a localised section of the material web (2). The DC resistance of the web is measured via the resulting field screening, to allow the corresponding humidity content to be calculated. The electrical field may be generated via rectangular voltage pulses, a sinusoidal AC voltage with periodic frequency modulation, or via a constant voltage, using a pair of opposing field electrodes (1,3) on opposite sides of the moving web. USE - For measuring residual humidity of textile, paper or photographic web material.