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:
Apr. 04, 1989
Filed:
Nov. 03, 1987
Applicant:
Inventor:
William J Alexander, Pittsburgh, PA (US);
Assignee:
Mine Safety Appliances Company, Pittsburgh, PA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340633 ; 73 2 / ; 324 / ;
Abstract
A catalytic gas detector circuit in which the temperature of a resistance gas sensing element, contained in a bridge circuit, is reduced and therefore stabilized by energizing a transistor to draw off current from the sensing element when the sensing element is exposed to high concentrations of combustible hydrocarbon gases.