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Title:
HIGH-TEMPERATURE GAS SENSORS AND THEIR USE IN EXHAUST GASES
Document Type and Number:
WIPO Patent Application WO2006046964
Kind Code:
A3
Abstract:
A method of sensing the amount of a gas in a fluid flow includes operating an acoustic wave (AW) sensor (110) at a first resonant frequency. The AW sensor includes a high temperature stable piezoelectric plate (112) coupled to a first gas-absorbing layer (122). Also included is combining a fluid flow having a gas component with the first gas-absorbing layer at a temperature of at least about 500 °C. At least one resonant frequency of the AW sensor is sensed. The amount of gas in the fluid flow is sensed by correlating the resonant frequency with the amount of gas absorbed in the first gas-absorbing layer. A sensor (110) for sensing the amount of a gas in a fluid flow includes a first gas-absorbing layer (122), a high-temperature-stable piezoelectric plate (112) coupled to the first gas-absorbing layer, and a controller (120) coupled to the high-temperature-stable piezoelectric plate. The controller is coupled to the high-temperature stable piezoelectric plate to measure a resonant frequency in the high temperature stable piezoelectric plate correlated with an amount of gas absorbed by the first gas absorbing layer, whereby the amount of a gas in a fluid flow is sensed. The high-temperature-stable piezoelectric plate is formed of at least one material selected from the group consisting of AlN, GaN, Al1-xGaxN (0=x=1), GaPO4, AlPO4, and materials having the crystal structure of Ca2Ga2Ge4SiO14, e.g., Ca2Ga2Ge4SiO14, La3Ga5SiO14, La3Ga5.5Nb0.5O14, La3Ga5.5Ta0.5O14.

Inventors:
TULLER HARRY L (US)
SEH HUANKIAT (US)
HYODO TAKEO (US)
Application Number:
PCT/US2005/012957
Publication Date:
September 21, 2006
Filing Date:
April 15, 2005
Export Citation:
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Assignee:
MASSACHUSETTS INST TECHNOLOGY (US)
TULLER HARRY L (US)
SEH HUANKIAT (US)
HYODO TAKEO (US)
International Classes:
G01N29/02; B01D53/86; B01D53/94; F01N3/20; F01N9/00; F01N13/00; F02D41/02; F02D41/14; G01N27/00; G01N29/00; G01N29/036; G01N29/22; G01N29/32; F01N3/08; G01N33/00
Domestic Patent References:
WO1996031773A11996-10-10
Foreign References:
US20030115860A12003-06-26
DE19931007A12001-01-25
Other References:
THIELE J A ET AL INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS: "High temperature LGS SAW devices with Pt/WO3 and Pd sensing films", 2003 IEEE ULTRASONICS SYMPOSIUM PROCEEDINGS. HONOLULU, HAWAII, OCT. 5, vol. VOL. 1 OF 2, 5 October 2003 (2003-10-05), pages 1750 - 1753, XP010701827, ISBN: 0-7803-7922-5
FRITZE H ET AL: "High temperature nanobalance sensor based on langasite", SENSORS AND ACTUATORS B, ELSEVIER SEQUOIA S.A., LAUSANNE, CH, vol. 76, no. 1-3, 1 June 2001 (2001-06-01), pages 103 - 107, XP004241101, ISSN: 0925-4005
FRITZE H ET AL: "Operation limits of langasite high temperature nanobalances", JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, ELSEVIER SCIENCE PUBLISHERS, BARKING, ESSEX, GB, vol. 21, no. 10-11, 2001, pages 1473 - 1477, XP004301702, ISSN: 0955-2219
TAMAKI J ET AL: "Application of metal tungstate-carbonate composite to nitrogen oxides sensor operative at elevated temperature", SENSORS AND ACTUATORS B, ELSEVIER SEQUOIA S.A., LAUSANNE, CH, vol. 25, no. 1-3, April 1995 (1995-04-01), pages 396 - 399, XP004309244, ISSN: 0925-4005
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