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Acoustic wave (AW) based moisture sensor for use with corrosive gases

United States Patent

5,571,944
November 5, 1996
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
Moisture corrosive gas stream is measured as a function of the difference in resonant frequencies between two acoustic wave (AW) devices, each with a film which accepts at least one of the components of the gas stream. One AW is located in the gas stream while the other is located outside the gas stream but in the same thermal environment. In one embodiment, the film is a hydrophilic material such as SiO.sub.2. In another embodiment, the SiO.sub.2 is covered with another film which is impermeable to the corrosive gas, such that the AW device in the gas stream measures only the water vapor. In yet another embodiment, the film comprises polyethylene oxide which is hydrophobic and measures only the partial pressure of the corrosive gas. Other embodiments allow for compensation of drift in the system.
Pfeifer; Kent B. (Los Lunas, NM), Frye; Gregory C. (Cedar Crest, NM), Schneider; Thomas W. (Albuquerque, NM)
Sandia Corporation (Albuquerque, NM)
08/ 359,510
December 20, 1994
This invention was made with Government support under Contract No. DE-AC04-76DP00789 awarded by the U.S. Department of Energy. The Government has certain rights in this invention.