Web moisture content measurement - is contactless through an electrode over material in electrical field with probes to register resistance

摘要

The contactless measurement of the residual moisture content of a moving web, uses the material's electrical resistance with an electrode (1) in the electrical field, over the material, in a linear shape with HT conductivity, parallel to the line of web travel. It is between two earthed metal surfaces (2). A charge signal is affected, and its level and time behaviour is registred by two successive charge measurement probes (3, 4) over the web and a side probe (5). From the law of charge build-up in the field and the subsequent discharge, the electrical resistance and the associated residual moisture content is estabilished. Also claimed is an assembly where the surfaces of the probes (3, 4) are on a plane parallel to the web surface. A rotating and earthed perforated, slitted or bladed disc in front of the probes rotates towards the material to modulate the charge signals received by the probes. USE/ADVANTAGE - The system is for the mesurement of the residual moisture content in a web of absorbent material such as textiles of or with a content of regenerated or natural fibres, paper and photographic film. The contacless action eliminates problems associated with electrode contact, in a more reliable measurement action.