System and method for measurement of traveling webs
AssigneeMeasurex Corporation
InventorsLeonard M. Anderson, Mathew G. Boissevain, M. Kent Norton
Life of this patent
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Abstract
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.
Claims22
A system for providing measurments, such as dry basis weight, of traveling webs of sheet material comprising:
- (a) illuminating means for directing substantially parallel rays of light substantially perpendicularly onto one surface of a traveling web simultaneously across substantially the entire width of the web;
- (b) a plurality of light detecting means to detect substantially parallel rays of said light emerging from the web perpendicular to the web surface;
- (c) enclosure means that environmentally isolate the illuminating means and the detecting means;
- and
- (d) signal processing means connected to the light detecting means for generating signals indicative of the quantity of light detected.
A machine for providing optical measurements of properties of a traveling web of sheet material comprising:
- (a) a first duct mounted to extend across one face of a web;
- (b) a second duct mounted to extend substantially parallel to the first duct across the opposite face of the web;
- (c) a first transparent member forming a wall of the first duct and a second transparent member forming a wall of the second duct, said first and second transparent members being located generally opposite one another to provide line-of-sight communication between the interiors of the said first and second ducts substantially across the width of the traveling web;
- (d) means to make optical measurements of properties of the web traveling between the first and second ducts by transmitting generally parallel rays of light perpendicularly onto the web via the first transparent member and detecting the intensity of substantially parallel rays of light emerging from the web substantially perpendicular to the web surface via the second transparent member.
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 sheet and having a transparent wall facing the sheet;
- (e) a plurality of light detector means mounted within the second duct to detect substantially parallel rays emerging frim the web, generally perpendicular to the web surface, said plurality of detector means being operable to provide electrical signals related to the optical intensity of the received light from identifiable locations across the web surface.
A method for optically determining properties of traveling webs of sheet material without scanning comprising the steps of:
- (a) transmitting modulated beams of collimated light through a duct;
- (b) reflecting rays from the modulated beams through a transparent wall such that the rays are parallel and are generally perpendicularly incident upon the surface of a traveling web to simultaneously and uniformly illuminate substantially the full width of the web;
- (c) detecting the intensity of generally parallel rays transmitted through the web generally perpendicular to the web surface at a plurality of adjacent locations;
- and
- (d) and providing electrical output signals proportional to the detected light intensity at least at first and second narrow bands of wavelengths at identifiable ones of said plurality of locations.
Dependencies are inferred from the claim text.