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:
Oct. 29, 1991
Filed:
Sep. 12, 1989
Edward L Tury, Brighton, MI (US);
Keith Kaste, San Luis Obispo, CA (US);
Ross E Johnson, San Luis Obispo, CA (US);
David O Danielson, Gregory, MI (US);
Sensors, Inc., Saline, MI (US);
Abstract
A non-dispersive infrared gas analyzer especially adapted for measuring the concentrations of HC, CO and CO.sub.2 in a vehicle exhaust includes a sample chamber for holding a sample gas, a radiation emitter for directing a beam through the chamber and a detector for indicating the amount of radiation absorbed. A plurality of filters, each of which transmit radiation at an absorption band of a gas component to be detected, are alternatingly positioned in the radiation path to produce a time-multiplexed signal having concentration information for all gases. A calibration assembly is provided which includes a plurality of calibration cells selectively positionable in the radiation path in order to provide an internal calibration standard for two-point calibration of each gas channel. The cells contain one or more of the gas components to be measured at concentrations and pressures predetermined to compensate for the difference in optical path length between the calibration cells and the sample chamber. A technique is provided for characterizing the calibration cells in situ after a conventional calibration, using bottled calibration gas, is performed.