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:
Aug. 03, 1993
Filed:
Feb. 25, 1992
Ake A Hellstrom, Columbus, OH (US);
Wim Muller, Westendorp, NL;
Steven P Sturm, Columbus, OH (US);
Alan M Reid, Columbus, OH (US);
ABB Process Automation, Inc., Columbus, OH (US);
Abstract
Characteristics of moving webs are measured using a radiation source shutter which is rotatably movable between an opened-shutter position and a closed-shutter position and structured to permit access to the radiation source in the closed-shutter position. The source is configured to produce a fan-shaped radiation beam which passes through the web to a detector. The sizing of the fan-shaped beam and the detector together with the spacing the source and the detector are such that the beam width is substantially less than the detector while its length is greater than the detector. This novel beam shaping, detector arrangement provides composition insensitivity, increases solid beam angle and superior streak detection by aligning the beam length dimension with the direction of web movement. Alignment insensitivity is obtained by tuning the radiation beam using concentric rings or crossed strips of material which is semi-transparent to the radiation to compensate for geometric characteristics of the radiation source/beam and the detector. Air within an open portion of a measuring column extending between the radiation source and detector is conditioned and also used to condition electronics associated with the detector. The gap between the radiation source and the detector is monitored and used to compensate for variations in the measuring column air mass due to gap variations.