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. 11, 2000
Filed:
Nov. 05, 1997
Applicant:
Inventor:
John Lindsay, Dorset, GB;
Assignee:
Zellweger Analytics Ltd., Orz, GB;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340635 ; 340632 ; 73 232 ; 73 2321 ;
Abstract
The presence of a serviceable electrochemical gas sensor (1) in gas detecting apparatus is determined on the basis of the noise in the output of a sensor amplifier. A microcomputer (22) calculates mean, rms or variance values for the noise in the output of the amplifier (20) for successive periods. Each of these values is compared with the threshold and if it falls below the threshold, counter is incremented. When the counter reaches a target value, it is determined fault condition as arisen and an alarm (23) is operated.