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US 7,678,329 B2Granted
NOx sensing devices having conductive oxide electrodes
AssigneeBabcock & Wilcox Technical Services Y-12, LLC
InventorsFrederick C. Montgomery, David L. West, Timothy R. Armstrong, Lonnie C. Maxey
Life of this patent
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Abstract
A NOx sensing device includes at least one pair of spaced electrodes, at least one of which is made of a conductive oxide, and an oxygen-ion conducting material in bridging electrical communication with the electrodes.
Claims29
A NOx sensing device comprising:
- (i) at least two electrodes wherein both electrodes comprise the same conductive oxide material, at least one electrode is configured for sensing NOx gas, and both electrodes are exposed to the same sample gas,
- (ii) an oxygen-ion conducting material in bridging electrical communication with said electrodes, said device being configured to sense at least one chemical selected from the group consisting of NO and NO2 when the device is biased at a selected electrical bias, and
- (iii) an electronics package including a means for measuring an electrical property between the first electrode and the second electrode, and an electrical biasing source for electrically biasing the sensing device, the electrical biasing source configured to produce a selected electrical bias between the first and second electrode, the electrical biasing source configured to produce the selected electrical bias, wherein the means for measuring an electrical property is selected from the group consisting of a voltmeter, an ammeter, and a combination thereof, and wherein the selected electrical bias is selected from the group consisting of electric current, voltage, and a combination thereof.
An apparatus for sensing NOx gas in a sample gas which includes oxygen, the apparatus comprising:
- (i) a first electrode;
- (ii) a second electrode, wherein both first and second electrodes comprise a first conductive oxide material, at least one electrode is configured for sensing NOx gas, and both electrodes are exposed to the same sample gas;
- (iii) an oxygen-ion conducting substrate in electrical communication with the first electrode and the second electrode, wherein the oxygen-ion conducting substrate, the first electrode, and the second electrode together define a sensing device,
- (iv) the sensing device having an electrical resistance that changes in proportion to the concentration of a member selected from the group consisting of (a) NO gas only and (b) NO gas and NO2 gas;
- (v) an electronics package including a means for measuring an electrical property between the first electrode and the second electrode, and an electrical biasing source for electrically biasing the sensing device, the electrical biasing source configured to produce a selected electrical bias, and
- (vi) the sensing device made of materials that change in electrical resistance in proportion to local concentration changes in a member selected from the group consisting of (1) NO gas and (2) NO gas and NO2 gas, when the sensing device is biased at the selected electrical bias, so that the change in electrical resistance of the sensing device while electrically biased indicates the local concentration of either (1) NO gas only or (2) NO gas and NO2 gas in the sample gas which includes oxygen.
3 more elements
Dependencies are inferred from the claim text.