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:
Jan. 23, 1990
Filed:
Jan. 23, 1989
Stephen C Pyke, Monroe, WA (US);
Harold E Hager, Bellevue, WA (US);
The Boeing Company, Seattle, WA (US);
Abstract
A detector and method for identifying a chemical vapor and determining its concentration in the ambient atmosphere. The chemical detector apparatus (120) preferably includes a plurality of surface acoustic wave (SAW) devices (10), each including a piezoelectric substrate (20), one-half (32) of which is coated with a selected polymer. The polymer characteristically absorbs one or more of a group of chemical vapors. Diffusion of a chemical vapor into the polymer increases its mass and proportionately changes the resonant frequency of the SAW device. A microcomputer control (186) is operative to determine a predicted time constant (or rate) for diffusion and a predicted equilibrium concentration of the chemical vapor within the polymer coating of the SAW device and to identify the chemical vapor and its relative concentration in the ambient atmosphere using the predicted values for these parameters long before the SAW device has reached equilibrium with the chemical vapor.