MEASURING SYSTEM AND METHOD OF TRAVELLING WEB

摘要

A system and method for optically measuring parameters such as dry basis weight of fibrous sheet materials during manufacture without scanning. The system includes mirror sections for reflecting modulated light as parallel rays perpendicularly incident upon one surface of a traveling web, and a plurality of light detection devices to detect light transmitted through the web at two distinct wavelengths. The system further includes ducts to environmentally isolate the mirror sections and the light detection devices.