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:
Nov. 02, 1999
Filed:
Jul. 11, 1997
Applicant:
Inventors:
Andrew J Dallas, Apple Valley, MN (US);
Kristine Marie Graham, Minnetonka, MN (US);
Timothy H Grafe, Edina, MN (US);
Assignee:
Donaldson Company, Inc., Minneapolis, MN (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
422 86 ; 422 83 ; 422 88 ; 436 38 ; 436 61 ; 436100 ; 436113 ; 436167 ; 436169 ; 436181 ;
Abstract
An indicator system provides a visual indication of the cumulative level of an airborne contaminant. An indicator has a transparent sheath with support medium treated with acid and a pH indicator, as the contaminant is adsorbed, the color changes along the medium. The indicator system may be used with an adsorptive filter system to predict the life of adsorption bed assemblies. A sample flow is taken upstream of the adsorption beds and is calibrated with a flow meter and valve. By monitoring the indicator, an accurate prediction of adsorption bed life may be made.