Method and device for detecting odorants in hydrocarbon gases
AssigneeBattelle Memorial Institute
InventorsMichael J. Murphy, Michael J. Swickrath
Life of this patent
Estimating the term…
Abstract
A dual quartz crystal microbalance (QCM) sensor is disclosed for use in a hand-held detection device (10) for detecting the presence of an odorant in hydrocarbon gaseous fuels. The odorant is a thiol-based compound, such as ethanethiol. One QCM (16) is coated with a coating typically containing a reagent that specifically reacts with the thiol of the odorant and alters its oscillation frequency as a result of mass gained in the reaction. A second QCM (16′) serves as a control and the two frequency signals may be heterodyned (26) to produce a delta-frequency representative of the mass change. Circuitry and signal processing (32) are used to produce a final result correlated to the level of thiol in the hydrocarbon gas.
Claims20
A portable device for detecting thiol odorants in a hydrocarbon gas, the device comprising a housing enclosing the following elements:
- i) a power source for producing a current;
- ii) a thiol sensor comprising
- a piezo-crystalline substrate disposed in the housing and located for gaseous communication with the hydrocarbon gas,
- a coating on the piezo-crystalline substrate, the coating capable of reacting specifically with and capturing thiol components from a gaseous phase thereby adding mass to the thiol sensor, while substantially not reacting with the hydrocarbon gas itself;
- and,
- iii) an oscillator circuit, the thiol sensor forming a part of the oscillator circuit,
- whereby, when powered by the power source, the piezo-crystalline substrate oscillates at a first frequency prior being exposed to thiol odorants in a gas, and at a second frequency after being exposed to thiol odorants in the gas and capturing thiols in the coating, the second frequency differing from the first frequency in proportion to the amount of thiol captured.
A portable device for detecting thiol odorants in a hydrocarbon gas, the device comprising a housing enclosing the following elements:
- i) a power source for producing a current,
- ii) a reference sensor comprising a first piezo-crystalline substrate disposed in the housing and located for fluid communication with the hydrocarbon gas;
- the reference sensor forming part of a first oscillator circuit capable of producing a reference oscillation frequency in response to a current input;
- iii) a thiol sensor comprising a second piezo-crystalline substrate disposed in the housing and located for fluid communication with the hydrocarbon gas;
- the second piezo-crystalline substrate having a coating thereon, the coating capable of reacting specifically with and capturing thiol components from a gaseous phase thereby adding mass to the thiol sensor, while substantially not reacting with the hydrocarbon gas itself;
- the thiol sensor forming part of a second oscillator circuit capable of producing a second oscillation frequency in response to a current input;
- and,
- iv) circuitry for heterodyning the first and second frequencies to produce a third frequency representative of the amount of mass added to the thiol sensor as a result of thiol capture.
Dependencies are inferred from the claim text.