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.

Date of Patent:
Apr. 23, 1985

Filed:

Jan. 31, 1983
Applicant:
Inventors:

John F Giuliani, Kensington, MD (US);

Henry Wohltjen, Burke, VA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ; G01N / ;
U.S. Cl.
CPC ...
436 96 ; 422 57 ; 422 58 ; 422 86 ; 422 91 ; 436111 ; 436113 ; 436165 ;
Abstract

A device for detecting small amounts of a chemical such as ammonia, and other ammonia-like molecules such as hydrazine or pyridine, in air and in other gases is disclosed. A capillary tube serves as a multiple total reflective medium for an optical beam from a light-emitting diode. The outer surface of the capillary tube is coated with a dye which, when exposed to the chemical, changes color so that the multiply reflected light is modified. The resultant change in the output light intensity from the capillary tube is photodetected and recorded to sense the presence of the chemical. When the chemical is removed, the dye returns to its original color so that the device can be reused.


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