US3725701A
Expired / Lapsed
US
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Fluorescent source non-dispersive infrared gas analyzer
Assignee: AC Inc
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Filing: 1971-10-26
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Granted: 1973-04-03
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Expires: 1991-10-26
Abstract
Abstract A non-dispersive infrared gas analyzer utilizing a fluorescent source including a specific gaseous compound whose presence in an unknown gas mixture is to be detected and a container having infrared transparent portions. Fluorescent emission from the specific gaseous compound is stimulated by, for example, a black body infrared source. A sample cell retains an unknown gas mixture in a position to receive fluorescent emission so stimulated while a suitable detector or transducer detects energy absorption by the unknown gas mixture of substantially any portion of the fluorescent emission spectrum of the gaseous compound being detected. An additional stage of selectivity is obtained by inserting a fluorescent filter between the sample cell and the detector. A standard for comparison is provided by a two-channel gas analyzer utilizing a standard cell or normalizing cell in addition to the sample cell. A standard for comparison is also provided by including in the fluorescent source a gaseous compound and enriched quantities of one or more isotopes of the gaseous compound to provide different but nearby wave lengths. A variety of arrangements for signal chopping and for shielding the black body infrared source from the sample cell is included.
Inventors
- 👤 W Link
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:57
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504; G01N21/37; G01N21/59; G01N21/61
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
41 words
A gas analyzer as set forth in claim 1 wherein said gaseous compound comprises C12O16 and wherein said isotopes are different CO isotopes formed by carbon and oxygen isotopes selected from the group consisting of C12, C13, O16, O17 and O18.
Claim 2
Dependent Claim
41 words
A gas analyzer as set forth in claim 1 wherein said gaseous compound comprises C12O216 and wherein said isotopes are different CO2 isotopes formed by carbon and oxygen isotopes selected from the group consisting of C12, C13, O16, O17 and O18.
Claim 3
Dependent Claim
41 words
A gas analyzer as set forth in claim 1 wherein said gaseous compound comprises N14O16 and wherein said isotopes are different NO isotopes formed by nitrogen and oxygen isotopes selected from the group consisting of N14, N15, O16, O17 and O18.
Claim 4
Dependent Claim
41 words
A gas analyzer as set forth in claim 1 wherein said gaseous compound comprises N14O216 and wherein said isotopes are different NO2 isotopes formed by nitrogen and oxygen isotopes selected from the group consisting of N14, N15, O16, O17 and O18.
Claim 5
Dependent Claim
41 words
A gas analyzer as set forth in claim 1 wherein said gaseous compound comprises N214O16 and wherein said isotopes are different N2O isotopes formed by nitrogen and oxygen isotopes selected from the group consisting of N14, N15, O16, O17 and O18.
Claim 6
Dependent Claim
43 words
A gas analyzer as set forth in claim 1 wherein said gaseous compound comprises S32O216 and wherein said isotopes are different SO2 isotopes formed by sulphur and oxygen isotopes selected from the group consisting of S32, S33, S34, S36, O16, O17 and O18.
Claim 7
Dependent Claim
60 words
In a non-dispersive infrared gas analyzer of the type in which absorption of selected infrared radiation by an unknown gas mixture in a sample cell is measured to determine the presence and amount of high concentrations of carbon monoxide, the improvement comprising: a detector cell for detecting radiation passing through said sample cell comprising a pneumatic cell filled with C13O16.
Claim 8
Dependent Claim
114 words
A gas analyzer comprising: a fluorescent source including a gaseous compound to be detected and a container for said gaseous compound having infrared transparent portions, said container defining a flow path between first and second locations, and means for transporting said gaseous compound from the first location to the second location; an infrared radiation source portioned at said First location for stimulating said gaseous compound; a sample cell positioned at said second location for retaining an unknown gas mixture in a position for receiving fluorescent emissions from said stimulated gaseous compound transported from the first location to the second location; and means for detecting absorption of said fluorescent emissions by the unknown gas mixture.
Claim 9
Dependent Claim
28 words
A gas analyzer as set forth in claim 9 wherein the flow path of said container between the first and second locations is coated with infrared reflective material.
Claim 10
Dependent Claim
92 words
A gas analyzer comprising: a fluorescent source including a gaseous compound to be detected in an unknown gas mixture, an enriched isotope of said gaseous compound and a single container for said gaseous compound and isotope having infrared transparent portions; means for stimulating fluorescent emission from said gaseous compound and said isotope; a sample cell for retaining an unknown gas mixture in a position to receive said fluorescent emissions; and means for detecting and comparing absorption by the unknown gas mixture of fluorescent emissions from said gaseous compound and said isotope respectively.
Claim 11
Dependent Claim
70 words
A gas analyzer as set forth in claim 11 wherein said detecting and comparing means comprises a first cell filled with said gaseous compound and a second cell filled with said isotope, said first and second cells positioned to receive radiation passing through the sample cell, a radiation detector for receiving emissions, and means for alternating impingement onto said radiation detector of emissions from said first and second cells respectively.
Claim 12
Dependent Claim
42 words
A gas analyzer as set forth in claim 11 wherein said gaseous compound comprises C12O16 and wherein said isotope is a different CO isotope formed by carbon and oxygen isotopes selected from the group consisting of C12, C13, O16, O17 and O18.
Claim 13
Dependent Claim
42 words
A gas analyzer as set forth in claim 11 wherein said gaseous compound comprises C12O216 and wherein said isotope is a different CO2 isotope formed by carbon and oxygen isotopes selected from the group consisting of C12, C13, O16, O17 and O18.
Claim 14
Dependent Claim
42 words
A gas analyzer as set forth in claim 11 wherein said gaseous compound comprises N14O16 and wherein said isotope is a different NO isotope formed by nitrogen and oxygen isotopes selected from the group consisting of N14, N15, O16, O17 and O18.
Claim 15
Dependent Claim
42 words
A gas analyzer as set forth in claim 11 wherein said gaseous compound comprises N14O216 and wherein said isotope is a different NO2 isotope formed by nitrogen and oxygen isotopes selected from the group consisting of N14, N15, O16, O17 and O18.
Claim 16
Dependent Claim
42 words
A gas analyzer as set forth in claim 11 wherein said gaseous compound comprises N214O16 and wherein said isotope is a different N2O isotope formed by nitrogen and oxygen isotopes selected from the group consisting of N14, N15, O16, O17 and O18.
Claim 17
Dependent Claim
44 words
A gas analyzer as set forth in claim 11 wherein said gaseous compound comprises S32O216 and wherein said isotope is a different SO2 isotope formed by sulphur and oxygen isotopes selected from the group consisting of S32, S33, S34, S36, O16, O17 and O18.
Claim 18
Dependent Claim
176 words
A gas analyzer comprising: a fluorescent source comprising a gaseous compound whose presence is sought to be detected and a container for said gaseous compound having infrared transparent portions; an infrared radiation source for stimulating fluorescent emission from said gaseous compound; a sample cell for retaining an unknown gas mixture and for receiving fluorescent emissions from said fluorescent source; means for continuously transporting stimulated gaseous cOmpound to a position for fluorescent emission into the sample cell comprising a flow tube filled with said gaseous compound defining a closed path and means for creating a flow of gaseous compound around the closed path, said infrared source positioned at a location along the flow tube for directing stimulating radiation into the flow path, said sample cell positioned along the flow tube downstream from the infrared source for receiving fluorescent emission from the gaseous compound, said sample cell positioned outside the path of radiation from the infrared source; and means detecting absorption of substantially any of the florescent emission spectrum of said gaseous compound by the unknown gas mixture.
Claim 19
Dependent Claim
115 words
In a non-dispensive infrared gas analyzer in which absorption of selected infrared radiation by an unknown gas mixture in a sample cell is measured to determine the presence and/or concentration of carbon monoxide, the improvement for detecting the presence and amount of high concentrations of carbon monoxide comprising: a fluorescent detector for receiving radiation passing through said sample cell for detecting absorption by the unknown gas mixture of the selected infrared radiation comprising a fluorescent filter including a container having infrared transparent portions filled with the carbon monoxide isotope C13O16 and a radiation detector positioned outside the optical path of radiation passing through the sample cell to receive secondary molecular emissions from said fluorescent filter.
Claim 20
Dependent Claim
128 words
A gas analyzer comprising: a fluorescent source comprising a gaseous compound to be detected and a container for said gaseous compound having infrared transparent portions; an infrared radiation source for stimulating molecular fluorescent emission from said gaseous compound; a sample cell for retaining an unknown gas mixture, said sample cell defining a flow tube exposed to fluorescent emission from said gaseous compound in a region along said tube and having a first temperature measurement means in said tube upstream from the exposed region and a second temperature measurement means in said tube downstream from the exposed region; and means detecting absorption of said fluorescent emission by the unknown gas mixture by the change in temperature of the unknown gas mixture before and after exposure to the fluorescent emission.
Claim 21
Dependent Claim
179 words
A gas analyzer comprising: a fluorescent source comprising a gaseous compound to be detected and a container for said gaseous compound having infrared transparent portions; an infrared radiation source for stimulating molecular fluorescent emission from said gaseous compound; a sample cell for retaining an unknown gas mixture and for receiving fluorescent emissions from said fluorescent source; means for chopping stimulated fluorescent emission from the gaseous compound incident upon said sample cell, said chopping means having a plurality of containers filled with said gaseous compound having infrared transparent portions, said containers mounted on rods radially extending from a central axis, with motor means for rotating said rods and containers about said axis, said infrared radiation source being mounted adjacent the circular track described by said containers for stimulating the gaseous compound in said containers as said containers sequentially pass said radiation source; said sample cell being positioned to receive emission from the stimulated gaseous compound and also positioned outside the path of radiation from said infrared source; and means detecting absorption of said fluorescent emission by the unknown gas mixture.
Claim 22
Dependent Claim
93 words
A gas analyzer comprising: a fluorescent source comprising a gaseous compound whose presence is sought to be detected and a container for said gaseous compound having infrared transparent portions, said container having flexible side walls to permit application of periodic forces to produce pressure surges in said gaseous compoUnd to stimulate fluorescent emission therefrom; a sample cell for retaining an unknown gas mixture and for receiving fluorescent emissions from said fluorescent source; and means detecting absorption of substantially any of the fluorescent emission spectrum of said gaseous compound by the unknown gas mixture.
Claim 23
Dependent Claim
109 words
A two channel gas analyzer comprising: a fluorescent source including a gaseous compound to be detected in an unknown gas mixture and a container for said gaseous compound having infrared transparent portions, said container having flexible side walls to permit application of periodic forces to produce pressure surges in said gaseous compound to stimulate fluorescent emission therefrom; a sample cell for retaining an unknown gas mixture in a position to receive said fluorescent emissions; a standard cell for retaining a standard gas mixture in a position to receive said fluorescent emissions; and means for measuring the differential absorption of said fluorescent emissions in said sample cell and standard cell.
Claim 24
Dependent Claim
98 words
In a non-dispersive infrared gas analyzer of the type in which absorption of selected infrared radiation by an unknown gas mixture in a sample cell is measured to determine the presence and/or concentration of a preselected gaseous compound the improvement comprising: a fluorescent source for providing selected infrared radiation corresponding to the absorption spectrum of a gaseous compound to be detected including a container filed with said gaseous compound having infrared transparent portions, said container having flexible side walls to permit application of periodic forces to produce pressure surges in said gaseous compound to stimulate fluorescent emission therefrom.
Claim 25
Dependent Claim
109 words
A gas analyzer comprising: a fluorescent source including a gaseous compound to be detected in an unknown gas mixture, an enriched isotope of said gaseous compound an a single container for said gaseous compound and isotope having infrared transparent portions, said container having flexible side walls to permit application of periodic forces to produce pressure surges in said gaseous compound and said enriched isotope to stimulate fluorescent emission therefrom; a sample cell for retaining an unknown gas mixture in a position to receive said fluorescent emissions; and means for detecting and comparing absorption by the unknown gas mixture of fluorescent emissions from said gaseous compound and said isotope, respectively.
Claim 26
Dependent Claim
99 words
A gas analyzer comprising: a fluorescent source comprising a gaseous compound to be detected and a container for said gaseous compound having infrared transparent portions, said container having flexible side walls to permit application of periodic forces to produce pressure surges in said gaseous compound to stimulate fluorescent emission therefrom; a sample cell for retaining an unknown gas mixture and for receiving fluorescent emissions from said fluorescent source; and means detecting absorption of said fluorescent emission by the unknown gas mixture by the change in temperature of the unknown gas mixture before and after exposure to the fluorescent emission.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |