The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 17, 1991
Filed:
Apr. 11, 1991
Ake A Hellstrom, Columbus, OH (US);
ABB Process Automation, Inc., Columbus, OH (US);
Abstract
A method and apparatus provide for determining properties of a web of traveling sheet material by scanning light including at least selected wavelengths such as IR and/or visible wavelengths across the web of material and also across at least two calibration samples. The signals generated in response to the scanning of the calibration samples is used to calibrate the scanning operation preferably on every scan. By providing at least two calibration samples, better estimates of average calibration parameters can be made and detection of a faulty calibration sample is facilitated. The calibration samples preferably are protected by mounting them within a scanner housing in relatively close proximity to a scanning beam generator. In addition, at least two compensation samples are supported substantially adjacent the moving web of material and preferably at least one compensation sample is positioned on each side of the web. By providing two compensation samples, fault conditions or fouling of either one of the compensation samples can be readily detected and also be used to better generate an average compensation signal. Compensation is particularly advantageous in accounting for ambient operating conditions of the process being used to manufacture the moving web of material. Both the calibration and compensation samples can be encapsulated in glass or other appropriate material to maintain their defined characteristics without effecting the monitoring operations of the optical scanner.