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:
Sep. 17, 1985
Filed:
Dec. 13, 1983
John E Tozier, Wexford, PA (US);
Abraham Anouchi, Pittsburgh, PA (US);
Richard Critchlow, Cheswick, PA (US);
Bacharach Instrument Company, Pittsburgh, PA (US);
Abstract
A constant temperature catalytic gas detection instrument (10) has a gas sensor (14) whose operating temperature is maintained within a predetermined range by a novel control circuit. The gas sensor includes a reference element (16) and an active element (18) on which a metal oxide catalyst reacts with the combustible gas. First and second driver circuits (30 and 36) are provided for presenting operating voltages to the active element (18) and the reference element (16), respectively, of the gas sensor (14). The first driver (30) controls the power to the active element (18), to maintain its temperature within a predetermined operating range. The second driver (36) responds to changes in the power through the active element (18) with respect to the current through the active element (18), causing the current in the reference element (16) to track the current in the active element (18). An indicator (38) connected between the active element (18) and the reference element (16) senses a potential difference therebetween to provide an indication of the concentration of said unknown gas.