System and method for measurement of traveling webs
AssigneeMeasurex Corporation
InventorsMathew G. Boissevain, Leonard M. Anderson, Michael K. Norton
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Abstract
A system and method for optically measuring parameters including dry basis weight, basis weight and moisture content of fibrous sheet materials during manufacture without scanning. The system includes means for reflecting modulated light as parallel rays perpendicularly incident upon one surface of a traveling web, and means to detect light transmitted through the web at least at four distinct bands of wavelengths.
Claims14
A system for determining optically-sensitive properties of traveling webs of sheet material during manufacture without scanning, comprising:
- (a) first duct means mounted to extend transversely of one face of a traveling web, the duct means having a transparent wall facing the web;
- (b) light source means arranged to direct collimated light lengthwise along the interior of the first duct means;
- (c) reflector means mounted within the first duct means to reflect said beams as parallel rays directed through said transparent wall generally perpendicular to the surface of the web to illuminate substantially the full width of the web;
- (d) second duct means mounted to extend generally parallel to the first duct means adjacent the opposite face of the web and having a transparent wall facing the sheet;
- and
- (e) light detector means mounted within the second duct means to detect the intensity of substantially parallel rays emerging from the web surface substantially perpendicular to the surface at least at four different ranges of wavelengths.
A method for optically determining properties such as basis weight, moisture content and dry basis weight of traveling webs of sheet material without scanning comprising the steps of:
- (a) directing rays from at least one beam of light such that rays from the beam are generally parallel and perpendicularly incident upon the surface of a traveling web to simultaneously illuminate substantially the full width of the web;
- (b) detecting the intensity of the parallel rays emerging generally perpendicularly from the web at least at four selected bands of wavelengths;
- and
- (c) providing electrical output signals proportional to the detected light intensity at each of said different wavelengths.
Dependencies are inferred from the claim text.